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5 steps to remove ic chips from the motherbaord

1. Heat surface mount resistors, transistors, diodes, with a miniture hot air blower or heat gun for 60 seconds.
2. Pull the ic chip from the motherboard.
3. Clean the contact area using a solder flux mix place a small drop on the contact area.
4. Place the component on top and then reapply heat with your blower or heat gun.
5. Clean with alcohol....done.

How do you test a transistor using cathode ray oscilloscope?

It's possible to test the transistor using Cathode Ray Oscilloscope (CRO)

CRO provides a function called "Component Testing". Just connect the transistor terminals between two pins provided by this function and you can observe the patterns on the CRO screen. Normally, in case of transistor, The operation is divided in few parts.

01. Observe the pattern for CB configuration.
---- For this, connect the terminals from CRO between this Collector and Base terminals and you can observe the pattern shown by CRO.

Same procedure should continue for CE & BE configuration so as to test the transistor.


LAPTOP MOTHERBOARD POWER ON DETAIL

V2000/m200/dv1000 power on steps detail signals with diagram and step explanation

3VPCU, 5VPCU , +5V, +3V 5VSUS, 3V SUS, NBSWON#, DNBSWON# SUSC# SUSB#, SUSON, MAINON, VRON S5_ON, HWPG, POWERGOOD, VCCP, VCORE SMDDR_VTERM, PWROK, RSMRST, PCIRST,CPUINIT,CPUPG, IMVPOK, CLK_EN# CPURST,

HP, CQ40 series power on boot process signals and chip detail

AD-OFF DCBATOUT TO_SYS. ACAVIN PWR_S5_EN 5V-PWR 3DE-PWR PWR-S5-EN 5V-PWR 3D3-PWR +3 VALW, +5 VALW +3 VALW, +5 VALW +3 VALW RSMRST-SB #3 ; z7 o# m8 [/ `+ I& j" Y! ^2 XBT-TH # PWR_BTN PWBTN-SB PM-SLP-S3 # PM_SLP-S4 ALL-PWRGD VR ON PM-PWPOK CPU PG PLT-RST

Dell laptop d600 boot process main signals detail

+ RTC_PWR5V & + RTC_PWR3_3V, + RTCSRC, (PWR_SRC) DCIN +, + DC_IN, SDC_IN +, ACAV_IN (+5 VALW & +3 VALW) LIVE_ON_BATT . power good VCC1_PWROK

+5 VSUS & +3 VSUS +2 _5VSUS & +1 _5VSUS PWRSW_SIO # SUS_ON +3 VSRC SUSPWROK_5V RUN_ON +5 VRUN, +3 VRUN, +1 _8VRUN, +1 _5V RUN, M7_MEM, M7_CORE, M7_1.8V SMDDR_VTERM 1.25V RUNPWROK CPU VTT VCC1_2_MCH RESET_OUT # VCORE_PWRGOOD, 1715PWROK, IMVP_PWRGD CPUPWRGD SLP_S1 # IMVP_PWRGD VTT_PWRGD # DELAY_IMVP_PWRGD

IBM T40 POWER BOOT DETAIL SIGNALS

VREGIN16, VINT16 VCC3SW , VCC5M , VCC3M , VCC1R2M VCC1R8M, MPWRGD, VCC3B, VCCCPUCORE for CPU, VBAT, DC –IN, VCC5B, VCC3A, VCC3B, VCC3P, VCC1R8A, VCC1R8B, VCC1R2A, VCC1R2B, VCC2R5A, VCCVIDEOCORE, VCCCPUIO, VCCCPUCORE


Component Level Motherboard Repair (Not replacement)

1) How do you diagnose the exact component failure?
Obviously, a burn mark is a dead give away, but what if there are no visual signs? Do you poke around with a multi-meter? With what voltage settings and how do you know what to look for?

2) Is it usually a bad capacitor?
badcaps seems to think so. What about a bad connection?

3) How do you perform the component level repair?
So you've found the bad capacitor or component, can you really solder a new one on without hurting the components around them? What's a good soldering iron for under $100?

Answers to your questions

Diagnose problem:
This is the hardest part in notebook repair. Basically, we measure voltages on motherboard and there are few power supply range from 1V to 12V on the motherboard. For example, north bridge needs 1.05V, 1.2V, 1.5V, 1.8V, 2.5V, depends on model of north bridge.

We also measure all sort of signals, such as PCIRST, CPURST, CLK. We measure the resistances of each AD line from north bridge to CPU/RAM.

We watch the current changing patterns to get rough idea where is the problem.

There are some simple steps to follow when checking a notbook motherboard:

1. make sure main system powers are ready, that is 3V and 5V.
2. switching circuit is ok, which involes IO/Keyboard controler, south bridge
3. power sequence is ok, which you can see the current jump up and down for few times.
4. all the necessary signals are not missing.
About Bad Cap
It happens but only about 10% in those motherboards need to repair, and it is the easiest fault to repair not matter if the cap was burnt or not.
Loose connection
Mostly happen on VGA chips, south birdges and the places close to CPU. Hard to troubleshoot and need lot experiences.

How to repair?
You need specialised tools. I have DC power supply which can display current change and set to different voltage and current output. You need Really nice soldering station, SMD rework station, BGA rework station, etc. I also have more than thousand schematic diagrams, all together about 10GB and you could not find anywhere in the net.

I have seen the video in youTub teach people how to fix VGA problem, and I guess you only have 30% chance if you follow it. My BGA rework station tutorial can perform up to 95% successful rate.


Troubleshooting Dead HP G6000 Motherboard

Things that are likely worth solving:

Bad capacitors. Decently common and the parts only cost a few cents.

Most of the ICs on board... 4-20 pin jobbies such as the power ic do fail and are swappable for less than a buck or so

Blown fuses. Easy to diagnose easy to replace. This is a definite.

Any and all damaged jacks. Power and audio being the most commonly broken.

Resistors. easy to find easy to replace. cost is in pennies

Transistors and diodes can be more problematic to diagnose and fix but they too are cheap and swappable with just a soldering iron.

Obviously you can swap cpus so you should be able to diagnose that as well.

Case Study 1

"Machine: HP G6000(same mainboard as V6000)

Problem: Laptop will not power up, completely dead

Discription: The machine has been water damaged. It does not have system standby power, which are 3V and 5V.

Finding The Fault:

Check Max8724(the battery charging chip) first, because to make system has standby power this chip must work correctly. This is a 28 pin chip, we only need to test 1, 2, 4, 8, 10, 11 pin. They are VIN(main power for chip), LDO(provide 3.3V for chip itself in order to set REF voltage, also provide signal to drive 2 MOS to charge battery), REF(set reference voltage of the chip), SHDN#(enable/disable chip, a switch), ACIN(indicate the power supply has plugged in), ACOK#(power adaptor ok with mainboard).

Everything ok except 10 pin, ACIN is 0V. This is incorrect, mainboard doesn?t detect there is an adaptor! Trace it backward and find it is very simple ? mainboard use 2 resistors to pull the input voltage(19V, directly from dc socket) down to about 4V, so test the first resistor and find it opened. Change it and 3V/5V power come up and mainboard be able to switch on.

Then the trouble start when I try to charge the battery. The charging current never go beyond 0.15A and after 10 seconds the charging light start to flashing. Also can?t switch on from battery. First, change Max8724, still same problem. Next check all the resistors around max8724 and change it if it has any sign of watering, still no good. Then change KB3926(EC/KBC, chip monitors the statue of battery), still same.

Decide to check MBDATA and MBCLCK, 2 signals that send battery information from battery to KB3926 before I give up. I find the MBDATA is short!

Finally, find there are 2 pins stick together on CN10(the connector of multimedia switch board). Fix it and it start to charging battery. Switch on with power adaptor, ok. Remove the power adaptor once switch on, battery keep the mainboard running, ok. But still can?t switch on from battery once remove the power adaptor. Think, think, do I miss something here or there? Oh, the CMOS battery not installed, put the CMOS battery back and everything work perfectly. The battery part of troubleshooting takes me about 3 hours.

Remember, system may not run if you don?t have CMOS battery or CMOS battery is low for some AMD cpu mainboard.


Case Study 2

"Machine: Acer 4600

Problem: Laptop will not power up

Discription: The machine wont turn on when customer bring in.

1. plug in our power supply and it shows short circuit on board, the current jump to the 5A, which is the limit of my power supply.

2. take off the mobo, drop the voltge of power supply to 5v, limit current to about 1A, plug in again and find a mos very hot.

3. replace this mos, now the short circuit fixed.

4. turn on, the current goes up to 0.3A and stopped, it should go up to 1A during booting.

5. touch cpu, not hot, no power to cpu.

6. check the cpu pwm, which is max1907a. all conditions to make it work are present, but still no power output. the ref voltege is 0. so most likely this chip gone.

7. I replace the chip and everything work fine.


For lots of unknow brand laptops, sometimes very hard to find drivers. I don't know how many people know there is a trick to install a similar driver.

Machine: TPG (can't see the model clearly)

Could not find the driver, TPG web site only point to Asus web site and doesn't give which model it clone from Asus. We can't find vga driver.

We use Everest to check what vga chip it use and find it is ATI IGP 320M U1. Download few from different web sites, all of them just give a message said could not find hardware it supports.

Finally, download a driver from fujitsu web site for the lifebook S2020(same vga chip and south bridge chip as TPG's). But still give the error message said no support hardware find.

Every device has a Device Instance ID, and windows will compare this ID with driver's INF. It will install the driver if it find a match ID and match SubSys, otherwise will give an error message.

We check the driver for S2020, find the string "PCI\VEN_1002&DEV_4336&SUBSYS_118110CF" in one of the INF file. We also find the Device ID on our machine is "PCI\VEN_1002&DEV_4336&SUBSYS_2029161F&REV_00". Device ID is matched but just into different sub system. Replace the string in S2020's INF with our Device ID string, driver is installed correctly and no error message.

Dell inspiron 6400 with a power problem.

Laptop can't run nor charge the battery on adapter, but on battery it's run.

This is typical protection circuit problem. check the 2 mosfet just after power socket

Charging problem

C700's charging chip is 39A126, DV6000/9000's charging chip is max8724 or max8725. Check the working conditions of those chips. such as VIN, ACIN, ACOK, LDO, REF, SHDN.

Charging problem is second hardest problem on notebook repairing, the first one is signal level ? everything looks ok but just no display.

usb no power

The following solution only apply that usb no power, if the usb device get power but can't be detected or can't be recognised by system, that indicates south bridge problem.

To get power for usb is very simple. use multimeter to find out which usb pin is ground, the pin on the other side will be the power. for example say pin 4 is ground so pin 1 will be the power.

connect power pin to 5v you can find on motherboard, usually a big inductor(becareful, when you measure the voltage, put battery in as well, some mobo the inductor for charging circut give you 5v if you don't put battery in but jump to battery voltage once you put in the battery, such high voltage will burn your usb devices). connect it on the different side of inductor that mosfet connect to(or should I say power out side?) so you can get smooth waveform, don't connect to the same side of mosfet(this is power in side).

Dark image on the screen , just very hard to see, a torch will show it is there though).

When we fix such problem, usually we do the following:

1. find an known good lamp or screen, plug into inverter see if its light up. if it lights up so you need to change your screen's lump.

2. if it not light up, do following:

a. check power(either 5V or 19V), enable signal(3V), brightness control(3V) are presented. (all testing by done with adaptor plug in).

b. if all those presented, then change inverter otherwise

c. need to find out which wire is power, which is enable, which is brightness people find hard in here because they don't know how to find out which is which.

Power always connect to fuse (also need to check fuse is ok). for the other two, you need to check inverter pwm's datasheet to make decision. Just start from pwm's EN and Brightness pin, trace back to connector. After you find out, make sure all these wires has normal resistance to ground, otherwise you have to cut off the wire that abnormal. Then try to find exact voltage from mobo and connect to inverter, by doing this you are not really fix the problem but bypass it. It is a easy to work around it rather than fix problem.

Q. The first step to troubleshooting is monitor the current change. usually, current reading can tell what was wrong and quite accurate. You frequently mention monitoring the current change to pinpoint the area of failure. Can you please describe this troubleshooting technique in more detail with some guidelines and numbers to look for?

A. To understand why current changing, you may need to know the basic powering states of notebook ? which is called ACPI standard ? S0 to S5.

S0 is full runing state, S5 is state that after you swith off laptop but with either power or battery presented. out off topic here, the S5 is the state after you shut down computer not the state you just plug in the power. Power button is for wake up computer from S5 and enter into S3. In ACPI standard, to switch on computers you need a signal "RSMRST". It explains why some laptops auto switch on if there is no CMOS battery, because its EC send RSMRST when power plug in. But you need push power button to switch on laptop if there is CMOS battery, because laptop remembers it is in S5 state.

Powering up a laptop can be divided into few parts, first check south bridge's gpio defination, check communcation between bios and south bridge, check system ram, power cpu, power up vga. so you can see the current goes up and down. step by step it reaches to full power.

Current changing monitor is just give you rough idea, sometimes not so accurate. let's see 2 examples:

1. a hp 530, power up but stay on 0.68A. it should go down a bit after 0.68A, and up again. The faulty mobo current change is 0.02 ? 0.3 -0.68. After we see this current, we know it may have problem on SB or may be on NB but most likely is SB.

I check LPC 0 to LPC 3, no signal find. it may have problem on SB or BIOS. So I flash the BIOS before I do anything on SB. It was fixed after I reflash BIOS.

2. DV9000. Normal mobo: 0.01 ? 0.3 -0.9 ? 1.1 ? 0.9 ? 1.2 -1.45 then display. we find faulty mobo 0.01-0.3-0.9-1.1-0.9, by checking DMI Link we find there is one or two pulses. So we have an idea that it already pass memory checking, the next stage is VGA checking and active VGA output. In here, if it stop in 1.1 it most likely NB or SB problem, but if it stop in 0.9 or after, it may be the problem of VGA.

Current changing gives you an idea about where is the fault but not 100% accurate. People ask me what fault by just give me the current reading and I always say you need to give me the changing states, how many jumps that current made.

Machine will run on charger with battery removed instal the battery and it will only run on the battery not the charger

Looks like discharging has problem. When discharging mosfet has problem, or the Gate voltage not correct, the 18V of main power will directly go to battery.

The current will be very large when you have short discharging mosfet, if you plug charger in and have battery installed at sametime. Laptop will detect this abnormal current and refuse to start up. Remove either one, machine can start up.

How to diagnose motherboards on a component level. What tools needed?

I find it is very hard to explain this. actually, it is very simple and can be described in two words: current and singal. read the current change during booting tells you where the machine stopped. check the singals on the different part of motherboard tells what is wrong or what is missing.

Tools are: smd rework station, bga rework station, power supply has current meter. all the rest tools you can find in any radio tv repair shop, of course all the datasheets for the components, especially the schematic diagram, you will find it much difficult without it.

What are common faults on mainboards? Do certain components fail?
Is there a trend as to which parts fail quite often?

Different maker/model has different common fault. Toshiba S1 is vga chip, and can't be repaired(well, almost can't be repaired because the pcb quality is not very good so successful rate is very low).

HP DV2000, 6000, 9000, compaq v3000, v6000, dell 1210, all those use nvidia chips have problem on vga chip or north bridge. easy to repair but have to make fan keep spinning after repaired, otherwise will break down in 1 or 2 week again.

hp nx5000, cpu pwm chip dry joint. acer 290, cpu pwm dry joint. hp dv1000, compaq m2000 protection circuit easy to blow up. ibm t40 vga dry joint problem.

These are just few of them. every machine has its own common fault. but dry joint is the common problem for all machines.

How to replace the graphics card on a dell 1420, the gfx card is a nvidia 8400gs

To fix such machine, first you have to do bga reworking on the chip, then connect fan to usb power to make it spin faster and non stop. also need to cut off fan controling wire.

could short on PQ8 make gate voltage high on both mosfets?
what do i need to check to find out why voltage is 19.36v.at gate

i have tested PQ8 and PQ9.results are as follows. PQ8 is AO4407. pin 1,2,3 is 19.37v. pin 5,6,7,8 is 19.36v. pin 4 gate is 19.37v.

PQ9 is AO4407. pin 1,2,3 is 19.37v. pin 5,6,7,8 is 11-12.00v. pin 4 is 19.37v.

i have set meter on diode mode and put positive on pin 2-3 and negative on 6-7 the meter beeps and shows resistance of 0.6 ohms,then i reversed the positive ? negative ,meter beeps again shows resistance of 0.6.it beeps both ways. this is PQ8.

i have done same as above with PQ9 and it shows resistance of 25kohm both ways.

Solution GATE PQ8 PQ9 Should be coneccted in the same line (trace) , if PQ8 is burn please check also PQ19 , another ao4407 are conected in the same DRAIN SOURCE , you need to remove from mobo and test in continuity or 200 Ohms scale , if you see 0 ? 10 Ohms betwen drain source is burn sure , check then PQ19 . You need 19v at PQ9 pin 5,6,7,8 but if PQ8 is burn not work . PU4 ISL6251 is the charger IC.

Toshiba sattelite P200-1JV laptop.it runs on battery without any problem.
it does not run with a/c. does not charge battery.

Solution first check all mobo marks to found mobo model and if you can found the schematic , then you need to found one mosfet 8 pin sop8 that is conected directly to DC JACK , and then found the next mosfet conected with the first mosfet , when you conect AC you need this 2 mosfet open , 19volts at DRAIN SOURCE , and about 8-10volts at GATE to open , usually is controled by the IC charger circuit , maybe have a short in AC circuit side or IC charger not recognize the adaptar and no open mosfets .

Having problems whit dell xps M1530

Dont do nothing when press power button , ACAV_IN is present at Q5 Q6 (3.2V) i have DCBATOUT but 3v and 5v not present , i check DCBATOUT for U69 TPS51120 and is OK , then check VREG3 VREG5 and also work fine , but i dont have 3V/5V_EN to activate outputs , Q17 is not in mobo only pads , D16 have 0.06v at 3V/5V_EN and 3.3v at PURE_HW_SHUTDOWN# , maybe need S5_ENABLE to activate 3v and 5v ? what you think about the next step to check ? maybe some signals in KBC WPC8763L .

Solution At the moment the TPS51120 is working , use power supply to put 2.5V in D16 3V/5V_EN and the 3V 5V outputs go enable . find why S5_ENABLE and 3V/5V_EN are low .

My D505 may power on boot OK or may have following condition.

a)LED flash

b)"da.da.da....." sound.

Solution If you know the bios manufacturer, the beep code will tell you where the failure is.
So the number of beeps and the duration of each beep is a specific code from the bios to let you know what it couldn't start ? like video, memory, cpu etc.
The north bridge dry joint, it is common fault of this model. BGA reworking on north bridge, and replace the north bridge if bga reworking doesn't work.

It's a Toshiba Satellite A205-SP4077, Core 2 Duo. While replacing cracked LCD tried several panels with no success.
Then noticed LVDS RX2- signal from motherboard is missing.

Solution The north bridge dry joint, it is common fault of this model. BGA reworking on north bridge, and replace the north bridge if bga reworking doesn't work.

A friend has an Acer, one of the alphabetic keytops has come off. It doesn't appear to be broken, but I'm having trouble clipping it back on. It's a weird double hinge, something like a Thinkpad, which I've fixed before (easily). Any insight into mechanical aspects of keyboards?

Solution First, put the retainer(or what you said "hinge") onto the keyboard base, then put the key on the top, slightly press down and lock the key on the retainer.

I currently have a HP DV6000 sitting in front of me with several rows of black/grey lines over the screen. Is it worth trying to fix yourself or should I just send it in for a warranty repair

Solution Send for warranty if it is still in warranty. To complete solve this problem, you need to replace Nvidia chip which was made after 30th week of 08.

A friend opened up his notebook to give it a clean but when he put it back together the bios is not finding the hard drive Solution Make sure you plug hard disk firmly.

It could be the problem of south bridge, the south bridge controls hdd. I have seen many times that clean cpu fan and end up with non working laptop.

I have a problem with a toshiba tecra M9 I bought the notebook on ebay. The seller said it was dropped, worked for a few days and then died.

Solution The common problem of this model is vga chip dry joint. check the hdd light flashing or not, it should be the vga if it flashes.

Note: The hardest repair laptop is dropped one, even harder than watering. The south bridge, north bridge and vga chip all could be dry joint. To fix such machine, I always resolder those big chips, sometimes it works and sometimes it is not. There is no good way to fix such machines, just simply take the chance.

Laptop has crashed and when you boot, the screen is split so there are 2 identicle screens vertically (1 above the other). It wont boot normally or last good config but will boot safely with networking but if it boots like this, wouldnt that suggest a hardware/bios issue.

Do you think if I heat up the VGA chip (or SB or NB) then the solder will melt and get fixed?

If so, what should I use to heat it up?

Solution I am not suggest you do that unless you have bga rework station. The temperature control must be very strickly. But if you want to take the chance, I suggest you use 2 hot air guns, one from top, one from buttom. Set the top temperature to 350, set the buttom to 300 and blow it about 10 min.

In the case you want to go ahead with such project. you must firmly fix both air guns and motherboard, not let them move when you blow the hot air. Use a little stick to touch the capacitors or resistors around the big chips, keep blowing about 5 min when the solder on small components reflowed. Don't forget to apply flux between big chips and pcb board. don't set buttom temperature too high, otherwise the components on the buttom may fall off. Good luck.

To be honest with you, I have less than 10% successful rate for dropped machines even I have a bga rework station. The watering boards I have more than 70% successful rate.

I have an issues with my girlfriend's old Acer Travelmate 3260 (bought 2007), the power input pin has broken and it no longer gets any power to the system. This gradually happened over time with it getting looser and not charging properly.

Do you have the schematic for this model and also do you have instruction on how to replace the power socket, plus where to buy the component from?

Solution You don't really need schematic for such repair job. The DC jack you can find on ebay, I think someone in uk sell all type of jack. you also can attach a cable if you couldn't find such jack, and such connector can be easily found in online.

Dual screen problems

Solution First, I don't think it is a good idea to use dual screens on laptop, you put extra loading onto the vga chip.

Second, the external monitor flicking means vga card try to setup the display mode and resolution on the monitor. It will be stable once it set the display mode and resolution.

Vga overheating

Solution There is overload to vga chip.

I still remember that back about 3 years ago I saw people modified their IBM Thinkpad, they use QXGA(resolution is 2048x1536) to replace original sxga(1400x900). The result of doing this is vga chip get overheat and kill machine fast, usually not over one year. But for the people can do such modify is no problem to fix their motherboard ? resolder the vga chip, or replace vga chip.

The more calculation of vga chip carried, the more heat it generated. Think about how many calculation jobs that vga chip has to do in your situation, not only the internal lcd, but also the external lcd. Much more than those people change lcd from sxga to qxga.

DV6000 laptop power switch problem

Solution The power switch from DV9000 is same as DV6000. There is other way to switch on your machine and you will know if is ribbon cable problem or m/b problem. It is handy if you have a multimeter. The switches of most laptop ( include dv6000) are just pull a voltage to the ground and send a signal to EC (most people call it keyboard controller). So check your ribbon cable connector on the motherboard, on the 3rd pin( can't remember from left or right, but it doesn't matter you can try both) it should have 3.3V, short this pin to the ground and your machine should power up. Don't worry you wouldn't damage anything even you short every pin on the connector to the ground.

Q. I have a Gateway P-6825 Laptop that has no backlight on LCD. I have bought 2 inverters 2 LCD cables I have tons of screens no matter what I get no backlight. It works perfect on external monitor and you can see it come on the LCD but the screen will not light up.
Also what is the normal input power to the inverter as well.

A. Inverter board input power sometimes is Vin or B+, close to AC adapter voltage. You may check if is there a fuse in the LCD connector path. I'd suggest you search for the inverter IC datasheet. For inverters using OZ960 there is an input called ENA which must be 3.3V for enable inverter and another called DIM which is 3V for full brightness. Hope this helps.

Q.I have a Toshiba Satellite Pro A300, just tried to use the dvd rom and it's not working, it won't acknowledge any dvd's, It won't even open, last time I used the dvd rom several months ago everything worked fine and the notebook has not been moved,

A. If the dvd drive it's ok (u should test it in another laptop), it's for sure a chipset problem (the chip that controlls the drive also, it's the intel ICH8M the U33A on the schematic/board).I will exclude a connection port problem if the laptop hasn't fallen or something like that.If drive is ok, try a reflow of that chip, should solve your problem.

Q.Is a Toshiba Satellite L355-D-S7901, motherboard 6050A2175001-MB-A02, after POST starts to beep continously like a stuck key. I've tried even with bare motherboard (no keyboard connected). Will appreciate any idea.

A. check capcitors that keyboard connected, or check keyboard controller.

How to check sony protection circuits

SONY VGN-NS11S MBX-195 M790 Rev 1.1 1P-0087J04-8011 PCG-7141M ,

Sony's protection circuits are hard to troubleshoot. It is involed too many components. About mbx-165 protection circuits:

1. Power pass PF1 becomes DC_IN, at this point, Max1909 start to work. ACIN, DCIN high, LDO 5V, REF 2V(must have, can't remember exactly voltage). Max1909_PDS low to drive PQ25 (don't know exactly voltage, but lower than DC_IN).

2. PQ25 convert DC_IN to DC_IN_MOS. Here comes the hardest to troubleshoot of sony protection circuit.

PQ26's gate must be low and it was a signal call DC_IN_G1. So where this DC_IN_G1 from? In normal situation, it max1909_pds through a resistor. Now, you have 19V of this signal that is abnormal.

we check it by few steps:

1. check pc3, is it short?

2. ac_off_3# is high? if it is high, check check PQ31, PQ20, PR116, PR119, PR120.

3. ac_off_3# is low? check the ac_off_3# signal, many components involved: DC_IN part from PD2 to AC_OFF_3#. From input of PU13 (2nd pin, max1909_LDO) to PQ24A, PQ59, PQ24B.

I hate sony's protection circuit, too many troubles. Last time I fix one of such problem on sony mobo is PD2 leaking, spend me almost 5-6 hours. And solution of it? Just remove the PD2, which means it does not matter if there is PD2 or not the mobo still working. Extra protection means extra troubles and faults.

Q. uSb power problem

A. The following solution only apply that usb no power, if the usb device get power but can't be detected or can't be recognised by system, that indicates south bridge problem.

To get power for usb is very simple. use multimeter to find out which usb pin is ground, the pin on the other side will be the power. for example say pin 4 is ground so pin 1 will be the power.

connect power pin to 5v you can find on motherboard, usually a big inductor(be careful, when you measure the voltage, put battery in as well, some mobo the inductor for charging circut give you 5v if you don't put battery in but jump to battery voltage once you put in the battery, such high voltage will burn your usb devices). connect it on the different side of inductor that mosfet connect to(or should I say power out side?) so you can get smooth waveform, don't connect to the same side of mosfet(this is power in side).

Q. My Lenovo SL400 screen went dark (image there, just very hard to see, a torch will show it is there though).

A. When we fix such problem, usually we do the following:

1. find an known good lamp or screen, plug into inverter see if its light up. if it lights up so you need to change your screen's lamp.

2. if it not light up, do following:

a. check power(either 5V or 19V), enable signal(3V), brightness control(3V) are presented. (all testing be done with adaptar plug in).

b. if all those presented, then change inverter otherwise
c. need to find out which wire is power, which is enable, which is brightness. people find hard in here because they don't know how to find out which is which.

Power always connect to fuse (also need to check fuse is ok). for the other two, you need to check inverter pwm's datasheet to make decision. Just start from pwm's EN and Brightness pin, trace back to connector. After you find out, make sure all these wires has normal resistance to ground, otherwise you have to cut off the wire that abnormal. Then try to find exact voltage from mobo and connect to inverter, by doing this you are not really fix the problem but bypass it. It is a easy to work around it rather than fix problem.

Q.
1. Is there a popular model of power supply that you can recommend?

2. Do you use mini-grabbers to attach power supply to laptop or do you have a collection of common dc plugs?

3. How do you use with Dell laptops that have a third wire to identify the power supply?

A.
I just burn one power supply today, this is 4th one I have burnt in last 3 years. Lucky it was not connected to any laptop when it was burnt. It's output voltage was jump from 19V to 50V, at this voltage all laptop's power circuits will burn throuhg, I have 3 laptops burnt before.

There is no popular model as I know, but at least 5A/30V. Get a industrial grade if it possible, becuase non-industrial grade power supply can't even run a laptop for more than one hour, or you face the risk to burn your power supply ? in turn it will burn the laptop. It is sufficent for repairing job but not enough for machine testing. It must have MA reading, because sometimes the reading is less than 0.01A.

I have all the collection of DC plugs, made from faulty chargers.

Ignor the 3rd pin of dell charger, it is only for PS_ID, only use for charging battery. Without this PS_ID machine still run but just can't charge. But some old dell like 5150 will not work our power supply, lucky we don't have any such machines to fix.

Q.
1. Is there a "generic" current profile for laptops or does each laptop have it's own unique current profile?

2. In your example for DV9000, you say "0.01 ? 0.3 -0.9 ? 1.1 ? 0.9 ? 1.2 -1.45 then display" Can you explain what happens at each current change state?

3. Do you need a power supply that logs the current or does it change slow enough to visually monitor the different current states?

4. If a laptop gets power but no video, how do you isolate the failure between northbridge,southbridge,SIO,bios?

A.
1. Every laptop has its unique current profile. But although the reading is different, the up and down (jumping) are similiar.

2. The dv9000's current reading may not very accurate, I suggest you first move the ram away and see how the current changing, then put back the ram and check it again.

3. not very fast, your eyes can catch the changes.

4. this is a big question, may need a full text book to explain it. The simple answer for this question: a. current reading, b. LPC wave, c.SMB wave. we have explain the current reading before. LPC waves are measured on EC, if you can't find LPC wave, that means no communication between EC and SB, PLTRST present or not, if is not then SB problem, etc. SMB waves are measured on ram slot, communication between ram and northbridge, H_RESET present or not, if it is not then NB. There are also so many signals need to check, can't remember what are them now.

I think the hardest fault for beginner is why the laptop not power up, not the faults after it powers up.

lets see the example how we troubleshoot a non-powering machine,:

Model:acer 5737

EC: kbc926

sympton: can't power up

checked: 3ALW, 5ALW presented

1. check the power button has power or not, press it to see if pull down the voltage.

2. check kbc926's 32 pin, which is on/off see the signal received.

3. EC_VCCA is high?

4. check EC_RSMRST is high?

5. LID_SW# is high?

6. ACIN is high?

7. EC_CRY is correct?(32.76Khz)

8. South bridge crystal correct( which is X4, also 32.76KHz)

9. PBTN_OUT pull low when you press power button?

if all above have no problem, consider the south bridge fault. for this machine, there is a single bridge ? south bridge/north bridge/vga combined. North bridge's functions are mostly taken over by CPU.

Q.
This laptop will run on ac charger it wilL NOT run on full charged battery.

A.
This is what we called protection circuit fault.

Looks like discharging has problem. When discharging mosfet has problem, or the Gate voltage not correct, the 18V of main power will directly go to battery.

The current will be very large when you have short discharging mosfet, if you plug charger in and have battery installed at sametime. Laptop will detect this abnormal current and refuse to start up. Remove either one, machine can start up.

Please Note:

The first step to troubleshooting is monitor the current change. usually, current reading can tell what was wrong and quite accurate.

CPU faulty is rarely happened. I only see no more than 5 to 8 cpu faulty during 10 years.

CPU kills motherboard happen on me once, and that motherboard in turn to kill another good CPU, and this is p3 cpu.

Don't worry about cpu, 99% chance it is good.

Try to do this, find a current meter, cut off the wire of power adaptor, connect current meter to the wire. The meter must be able to read at least 0.01A.



New Bios VS Old Bios

Change to 'Bios' will make for PCs that boot in seconds

New PCs could start in just seconds, thanks to an update to one of the oldest parts of desktop computers.

The upgrade will spell the end for the 25-year-old PC start-up software known as Bios that initialises a machine so its operating system can get going.

The code was not intended to live nearly this long, and adapting it to modern PCs is one reason they take as long as they do to warm up.

Bios' replacement, known as UEFI, will predominate in new PCs by 2011.

The acronym stands for Unified Extensible Firmware Interface and is designed to be more flexible than its venerable predecessor.

"Conventional Bios is up there with some of the physical pieces of the chip set that have been kicking around the PC since 1979,"

The original Bios only expected it to have a lifetime of about 250,000 machines - a figure that has long been surpassed.

old bios was never really designed to be extensible over time.

The age of the old Bios was starting to hamper development as 64-bit computing became more common and machines mutated beyond basic desktops and laptops.

"Drive size limits that were inherent to the original PC design - two terabytes - are going to become an issue pretty soon for those that use their PC a lot for pictures and video,"

As tablet computers and other smaller devices became more popular, having to get them working with a PC control system was going to cause problems with old bios.
because old Bios expects the machine it is getting going to have the same basic internal set-up as the first PCs. As a result, adding extra peripherals - such as keyboards that connect via USB rather than the AT or PS/2 ports of yesteryear - has been technically far from straightforward.

Old Bios forces USB drives to be identified to a PC as either a hard drive or a floppy drive. This could cause problems when those thumb drives are used to get a system working while installing or re-installing an operating system.

New Bios (UEFI) frees any computer from being based around the blueprint and specifications of the original PCs. For instance, it does not specify that a keyboard will only connect via a specific port.

"All it says is that somewhere in the machine there's a device that can produce keyboard-type information," Under UEFI, it will be much easier for that input to come from a soft keyboard, gestures on a touchscreen or any future input device.

"The extensible part of the name is important because we are going to have to live with this for a long time,"

The New Bios called UEFI started life as an Intel-only specification known as EFI. It morphed into a general standard when the need to replace Bios industry-wide became more widely recognised.

Alternatives to UEFI, such as Open Firmware and Coreboot, do exist and are typically used on computers that do not run chips based on Intel's x86 architecture.

The first to see the benefits of swapping old-fashioned Bios for UEFI have been system administrators who have to oversee hundreds or thousands of PCs in data centres or in offices around the world.

Before now, getting those machines working has been "pretty painful" because of the limited capabilities of old Bios.

By contrast, he said, UEFI has much better support for basic net protocols - which should mean that remote management is easier from the "bare metal" upwards.

For consumers, the biggest obvious benefit of a machine running UEFI will be the speed with which it starts up.

"At the moment it can be 25-30 seconds of boot time before you see the first bit of OS sign-on," he said. "With UEFI its getting under a handful of seconds."

Some PC and laptop makers are already using UEFI as are many firms that make embedded computers.


LAPTOP to IDE HARD DRIVE ADAPTER


The question always comes up, "Can I hook up my laptop hard drive to my desktop?"  The answer is yes with the proper adapter. You will need a 44 pin to 40 pin IDE adapter.

The connector adaptor converts a laptop HDD 2.5 inch connector to a 3.5 inch HDD connector as used in the IDE bus system.  It is powered by a 5V Molex plug.

This allows the use of a laptop hard drive with a 44 pin connector in a standard tower or desktop PC on the 40 pin IDE cable.  You will have to set the laptop hard drive as a Master or Slave depending on your Desktop configuration.

This adaptor will not work for plugging a standard IDE type hard drive into a laptop drive controller.

Laptop to IDE HDD  Adapter
 
NOTE:  It's important to properly connect both ends of the adapter to ensure functionality and prevent the possibility of shorts.  On the IDE interface end, the red wire on the ribbon represents pin 1.  On the HDD, pin 1 should be labelled by the drive's manufacturer.  Pin 1 on the adapter is shown in the this graphic.
Laptop to IDE HDD  Adapter



Power Drain: A simple solution to fix Laptop problems

Ever had to wait for several minutes for your laptop to boot up?
Wish you can fix it in a few seconds, well maybe this would be helpful for you.

It can be really irritating when your laptop/netbook is slow or has choppy sound, or a noisy harddisk, or touchpad problems. There is a way to fix it easily and very safely, the best part is you dont have to spend a cent or install any software.

This simple fix is called a power drain.
It will release all the excess power that gets stored in the laptop which may have caused your computer’s hardware to malfunction. Simple hardware problems caused by excessive power supply can be solved by performing a power drain.

Just follow these steps:

  1. Shutdown the laptop/netbook.
  2. Unplug the AC power cord (charger) from the laptop and remove the battery. Be careful and make sure you dont break anything.
  3. Now with the battery and charger unplugged, just press and hold the power button of your computer for 20-30 seconds.
  4. Now release the power button, plug in the battery and turn on the computer. It should perform much better now.

Tips to increase the battery life:

  1. Avoid charging the battery for too long.
  2. Also avoid using the computer while the battery is being charged.
  3. Turn off the computer when you dont use it.

This can be helpful for a Desktop computer too:
For desktop computers,take a note of the cords and where they plug into. If you dont know about this ask an experienced friend to try this.

Unplug all the cords from behind the cpu, press & hold the power button for 30 seconds. Replug all the cords and turn on the computer.


Problem: Waterlogged laptop

Cost: $4
Time: About 20 minutes (followed by overnight drying)
Materials: Towel, screwdriver, compressed air -- and hope

Why is it that when there's a glass of water or coffee to be spilled, a notebook is generally there? Call it Murphy's Law of Mobility, but I've seen several notebooks die because of spills.

If you've spilled a soda or a caramel macchiato into your notebook, you're probably out of luck. Anything with sugar is death -- once it dries it's there forever, eating away at your system's components. At that point, you could send it to a professional to use deionized water and a lot of patience, which can be a $1,000 job and take weeks, but you're probably better off just pulling out the hard drive and buying a new machine.

If it's just water or non-sugared coffee that you've spilled, your chances of saving it are much better. Although it's important to act quickly, the worst thing you can do to a wet system is start it up right away to see if it works. If there's water inside, you run the risk of creating an electrical short and potentially causing permanent damage. The thing to do is to calm down and dry out the system before hitting the power button.

Quickly unplug the machine and take out all of the easy-to-remove components like the battery, CD drive, hard drive and keyboard, and set them aside to dry separately. (You'll need a screwdriver to remove some of these parts; consult your manual for instructions.)

Carefully tilt the laptop on its side to help the water drain out.

Tilt the system on its side to help drain the water out. Do yourself a favor and put a towel underneath. Try to keep the liquid away from the display as you're removing parts and draining the system.

Gently shake the system to get liquid out of the many nooks and crannies inside; the air vents generally act as water canals. Next, use a can of compressed air to blow the inside of the case as dry as possible.

Use compressed air to help dry the insides.

It's a good idea to let the machine sit near a heating or cooling air vent overnight -- or longer if you can stand the suspense -- to fully dry it out.

When you're sure the system has dried out, put it back together, start it up and hope for the best. If it starts OK, let it run for a while to remove any remaining condensation or droplets. If it doesn't start up, it's time to consider getting a new machine.


Problem: Scratched screen

Cost: $5
Time: 5 minutes
Materials: Toothpaste, cloth, window cleaner

Replacing a screen and its inverter electronics is a tough job that can cost several hundred dollars and take hours. For an old system, it's likely not worth it. But if the display is only slightly scratched, it's a no-brainer to fix it.

After a trip to the beach on a windy day last summer, I noticed a bunch of small scratches and one big one on the display of my Intel Classmate PC netbook. The scratches annoyingly obstructed the screen's image.

My netbook had one big scratch and several small ones.

These types of scratches can be smoothed out with a dab of toothpaste (and I do mean toothpaste -- the gel varieties usually don't have the necessary abrasives) and a little elbow grease.

Gently rub toothpaste into the scratches.

Rub the toothpaste between your thumb and forefinger and it should feel slightly sandy and gritty. It's these mild abrasives that will fix the screen's problem.

Gently rub the toothpaste in a circular motion over the scratches for a few seconds (not too hard -- you could rub off the screen's surface coating).

Then wipe the screen clean with a soft cloth.

While the large scratch isn't gone completely, the smaller ones are.

Finish up by cleaning the screen with a non-ammonia-based window cleaner. My favorite is Sprayway, but there are grocery store shelves filled with these products. Look it over and if the scratches aren't gone, repeat the process.

This strategy isn't perfect. With my netbook, the toothpaste only partially removed the big scratch, but it did get rid of all the minor scratches. Plus my netbook now has a minty fresh aroma.


What do I do if my battery will not charge to 100%?

There is a common Windows bug that does not recognize a newly installed battery. To fix this problem, RIGHT click on My Computer, then click on Properties. Click on the Hardware tab, then click on Device Manager. Click the plus sign next to Batteries and delete the Microsoft AC Adapter and Microsoft ACPI-Compliant Control Method Battery items. Shut down the system. Unplug it for a minute, then plug it back in and reboot. When Windows starts, it will identify the battery and start charging it fully. If this does not fix the problem, you probably have a defective battery or a battery with incompatible firmware.

What is the best way to charge my new battery?


There are two schools of thought on this. First, charge the battery to full for about 8 hours before you use it, then discharge it fully. Do this about three times. Second, use the battery in its current state and drain fully. Then recharge for 8 hours and discharge fully again. Do this about three times

How can batteries be connected


When interconnecting batteries (cells), they must be identical in voltage and amp rating!

Batteries may be connected in series. the positive terminal of the first battery is connected to the negative terminal of the second battery; the positive terminal of the second is connected to the negative of the third, and so on. the voltage of the assembled battery is the sum of the individual batteries. The batteries are connected: + to - to + to - to + to -, etc. The capacity of the battery is unchanged.

Batteries may also be connected in parallel. The positive terminal of the first battery is connected to the positive terminal of the second battery, the positive terminal of the second is connected to the positive of the third; the negative terminal of the first battery is connected to the negative terminal of the second battery, the negative terminal of the second is connected to the negative of the third and so on. The batteries are connected: + to + to + and - to - to -. In this configuration, the capacity is the sum of the individual batteries and voltage is unchanged.

For example, (5) 6V 10AH batteries connected in series produces a battery array that is 30 Volts and 10AH. Connecting the batteries in parallel produces a battery array that is 6 Volts and 50AH. Ordinary auto batteries are designed in the same fashion. Six 2-volt cells are arranged in series to produce a 12v battery. Many Ni-Cd batteries are arranged in the


Problem description:

Basic description of the design:

18volts + ground comes into the dc power jack - 2 wires carry the current about 4 inches and a plastic connector splits it into 2 18volt wires and 2 ground wires - they attach to the motherboard (where I have all good connections).

Ac input has somehow fused with the battery input - and in turn disconnected itself so that the laptop believes that both the battery - and the ac input are BOTH battery.

Notes:

1 When a fully charged battery is installed laptop works perfectly

2 When battery is removed ? and ac cord plugged in ? laptop gives fast blinking lightening bolt (warning that the battery is too weak to be used ) ? of course the battery is NOT INSTALLED ? so this blink error should not be happening.

Tested:

Ac power adapter. = Good
Battery = Good
Correct voltage reaching the motherboard through the cables.

The laptop seems to think that a weak battery is attached (when NO battery is attached and the ac adaptor is plugged in)

Solution: Change the capacitor chip on the motherboard that is causing the problem.

Testing Battery Terminals

There are SIX terminals on the battery; with the battery removed the power throughput on each motherboard battery connection should change.

Battery removed on a good laptop=
1: negative
2: +3.31 volts
3: negative
4: +5.0 volts
5: +5.0 volts
6: +1.44 volts

Battery removed on DAMAGED laptop=
1: negative
2: +.77 to +.89 constantly changing voltage
3: negative
4: +1.2 to 1.30 constantly changing voltage
5: +1.15 to 1.30 constantly changing voltage
6: +4 to +7 constantly changing volts

It is obvious to me that with varying power outputs like this - all at such low numbers I can not expect this laptop to start up - So one of the parts between the ac input and where the battery input goes must have gone bad - because with the battery installed the voltages go back to normal; and of course the battery will never charge...

Battery Installed on a good laptop (same readings on damaged laptop)

1: negative
2: +2.0 volts
3: negative
4: +5.0 volts
5: +5.0 volts
6: +16.0 volts (probably changes slightly depending on the strength of the battery)

Why does the laptop battery power reduced even if i don't use it


Because of the humidity and non-insulated environment. All the batteries will be discharged naturally. It depends on the quality and newness grade. It is normal to reduce 1% power in 3-4 days.

The New Battery Isn?t Charging. What?s the Deal


1). New batteries are shipped in a discharged condition and must be charged before use. We generally recommend an overnight charge (approximately twelve hours). Refer to the user's manual for charging instructions. Rechargeable batteries should be cycled - fully charged and then fully discharged two to four times initially to allow them to reach their full capacity. (Note: it is normal for a battery to become warm to the touch during charging and discharging).

2). New batteries are hard for the device to charge; they have never been fully charged and are therefore "unformed". Sometimes the device's charger will stop charging a new battery before it is fully charged. If this happens, remove the battery from the device and then reinsert it. The charge cycle should begin again. This may happen several times during the first battery charge. Don't worry; it's perfectly normal.

The Don?ts and Do?s of Battery Use


Battery Don'ts


1.  Do not short-circuit. A short-circuit may cause severe damage to the battery.

2.  Do not drop, hit or otherwise abuse the batery as this may result in the exposure of the cell contents, which are corrosive.
 
3.  Do not expose the battery to moisture or rain.

4.  Keep battery away from fire or other sources of extreme heat. Do not incinerate. Exposure of battery to extreme heat may result in an explosion.


Battery Do's


1.  Fully charge/discharge battery up to 4 cycles before achieving full capacity of a new battery.

2.  Fully discharge and then fully charge the battery every two to three weeks for battery conditions.

3.  Run the device under the battery's power until it shuts down or until you get a low battery warning. Then recharge the battery as instructed in the user's manual.

4.  Remove from the device and stored in a cool, dry, clean place if the battery will not be in use for a month or longer.

5.  Recharge the battery after a storage period.

6.  Ensure maximum performance of the battery by optimizing the device's power management features. Refer to the manual for further instructions.


What is DC JACK ?


A DC jack is a component used in many electronic devices that allows a steady power source to be plugged in. Though electronics require direct current (DC) power, alternating currentAC) is the type of electricity supplied to and available in household wall sockets, mainly because of its ability to be delivered over long distances without losing strength. Therefore with most electronics, an AC adapterconnected to a DC jack is necessary to supply power in a usable way.

Unlike AC plugs, which are uniform and regulated on a country-by-country basis, DCjacks and plugs, which are technically referred to as coaxial power connectors, are generally not standardized. Many electronics manufacturershave their own proprietary AC adapters, also known as power bricks, which employ unique sizes of DC jacks. Currently Germany and Japan are the only countries that have attempted to issue standards for DC jack sizes. Different AC adapters and DC jacks can vary in many ways, ranging from voltage to physical diameter.

How to replace a laptop dc jack ?


Click here for the picture tutorial
Fixing a dc power jack on your (or someone else's) laptop can be difficult. If you are not sure what you are up against is a sure sign that you may not be able to reassemble the laptop. However with the proper steps, repairing, or replacing a laptop dc jack can be accomplished.

0) As step zero, it is important to make sure that you identify a bad dc jack. If a laptop isn't charging when it's plugged in combined with a very loose power jack port usually indicates you have a bad dc jack. We have also seen dc jacks that are just fine, however when looked inside, you see it has been physically destroyed on the rear end of the jack itself. Each case is mostly different, but you will run across 3 possible scenarios.

a) The dc jack has cold solders and it just needs to be resoldered (the most common).
b) The dc jack has been broken in unseen areas of the jack itself (common diagnosis is the wiggling of the jack with the adapter).
c) There is nothing wrong with the dc jack and it's an issue with something else on board (uncommon, but it happens).

1) Do your research.

So you conclude that you have a bad jack. Find out what style or sort of power jack you need for the laptop. You don't need to open the laptop to find out what type of power jack you need. Go to the internet and search for model laptop + dc jack. For example, if you have a Toshiba Satellite, search the internet for ?Toshiba Satellite dc jack?. You will be greeted with some useful results. Not only will it give you results for dc jacks but they look like in general. It would not be beneficial if you ordered a random dc jack that doesn't even fit inside the notebook.

At this time, it would be best to check to see if the laptop powers on. If here is enough battery life left, turn it on to ensure that the laptop works fine. It may be essential after reassembly which we will explain later

Some models like Toshiba Satellites will have a dc jack with different pin sizes. The pin in the middle of the jack will be a different gauge or different size. It?s crucial that you check to ensure that you get the correct jack size. Failure to do so will ensure you some problems when you plug in your Power adapter (ie: it won't fit). When you receive your dc jack in the mail, fit it on the power adapter that goes the notebook to make sure that you received the right dc jack.


Click here for the picture tutorial
2) Prepare and gather the tools you need. Make sure you have the right tools for the job.

- Screw Drivers (different sizes and shapes)
- Paper
- Pen or Pencil
- Packaging Tape
- Soldering Iron (and soldering essentials)
- Volt meter (to check continuity)
- Basic electronics and soldering knowledge

Make sure you have different types of phillips screw drivers, flat headed screw drivers, hex screw drivers, torque screw drivers, etc. If you have never been inside your laptop, then you don?t know what to expect.

3) Visual overview and time to get to know your laptop. This one is what we consider an important step, but it can easily be missed.. Before are ready to disassemble a laptop, we always look at every single screw hole, removable piece and potential issues. It's just a practice that we perform to help me remember where the nooks and corners are. Take about 5-10 minutes to sit down and rotate the laptop around and look at it in more detail.

Time to get started?

4) Remove the external devices. By external devices, this means the Hard Drive, Battery, PCMCIA devices if you have any, etc. When you remove these devices, you will see screws in new places and it will obviously make it easier to access the laptop when disassembly occurs. The CD ROM from a laptop, most of the time, cannot be removed at this point. When you start removing screws, it may be easier to remove the CDROM later but not in the beginning.

5) Disassembly and documentation of your steps. This is where the paper and pencil come in. The most important tactic you need to perform during the disassembly process is the documentation. We cannot emphasize enough the need to document where every single screw location and size.

The most general place to start disassembly is on the bottom of the laptop. It has the most accessible screws. Generally what you want to do is draw on a piece of paper a rough diagram of one laptop. Draw one side of the laptop per page. On the diagram, label where screws are located on the laptop. Be as descriptive as possible about the location of the screws and their location.

When you remove screws, use the tape to stick them near the hole where they came from. In case the tape fails, the diagram you draw will assist you in putting them back where they belong. Document the order in which pieces are removed. Another solution is to collect all the screws from a section, tape them in a little bundle and stick them in a notable location.

Some laptops have only 2-3 sizes of different screws. There are many laptops that have many different sized screws. Take the time and document where each screw comes from. IBM Thinkpads are nice. They actually have a sticker that shows the label of screws and screw sizes. It comes in handy. Some Toshiba's also have a label next to screw holes and give you unique identifiers.

Once again, it's essential that you document each step you take during the disassembly of the laptop!

6) Handle with care. The Plate connector beneath the LCD is the most fragile piece of the laptop disassembly. That's why we gave it it?s own mini-section.

It?s the most fragile because if you force to plate too hard, you will snap or damage it. Some models have it just tied down by a few screws underneath the laptop. Most models have a snap action to it. It comes in handy to use a very thin flat head screw driver to probe the plate. If the screw driver bends too much, then it's time to probe in a different section. Please be cautious when doing this. A good place to probe is on the hinges where the plate overlaps next to the LCD hinge. When you start pulling up on the hinge from the corners, it will start exposing the parts underneath it.

(Note: The LCD display will not have to be disassembled fully. Just the cord and hinges can be removed alone. You do not have to get into the insides of the LCD.)

7) Motherboard access review. You've disassembled the laptop and you have the motherboard in your hands. Look at the dc jack and it?s connection to the motherboard. One issue we see with dc jack failure is cold soldering or failure in the solder itself. If there is not damage to the dc jack, the jack can be repaired by re-soldering the current dc jack in place. Some of the time, the dc jack itself is damaged and needs to be replaced.

8 ) Replace / Repair the laptop dc jack. If the dc jack needs to be replaced, use your soldering iron to heat up the solder from the dc jack and remove the old jack. If you have a dc jack with hooks or curves in the connector, good luck. We know how difficult it is when removing this type of dc jack, but with some patience and persistence, it can be done. When the dc jack is removed, clean the area (pin holes); then solder in the new dc jack into it's slot.

Warning: Some motherboards have very thin rings around the dc jack connectors themselves. The older Sony Vaio laptops have them. If you heat the solder too hot or too long, these rings come off. When that happens, you might as well call it game over. These rings connect the dc jack to the motherboard using extremely thin connections. The rings are vital to the dc jack connection to the motherboard. It is very easy to burn, or break the system board during this process.

When you get the new dc jack in the slot, you have the option of putting hot glue around the corners of the new dc jack. It?s an option to prevent the dc jack from getting bumped and pushed too much from the ac adapter. It's just added strength. Just don?t over-do it if you decide to put some on.

BE CAREFUL ABOUT THE CHIPS AND ELECTRONICS AROUND THE DC JACK!
Click here for the picture tutorial

People have destroyed chips on laptops because they were not careful when de-soldering and soldering. A sharper soldering iron is a better tool than a blunt rounded soldering iron.

9) Test your continuity. It sounds impossible, but you can test to make sure that you connected your dc jack correctly. Most volt meters have a continuity checker on them. Check to make sure the grounded section of the dc jack properly grounds, and if possible, check to ensure that the positive pin on the dc jack is properly connected to the motherboard. You can do this by touching some of the diodes on the motherboard close to the jack. You will know if it registers.

10) Reassembly with a little faith. This is the moment of truth. If you documented your disassembly well, then it will be your road map to reassembling the laptop. Start reassembling the laptop in the reverse order in which you disassembled it. Make sure you plug in every little cord, and ribbon back into your laptop. Disassembling the laptop again because you forgot a wire or ribbon is just annoying to the max.

11) Testing the laptop. Test the battery first to make sure that the laptop turns on without the dc jack. There have been a few situations where people have worked on their laptop and it didn?t turn on after they reassembled it. This is unfortunate, but it does happen. Sometimes you damage something during the whole process, but with caution it can be avoided.

Once you verified the laptop turns on with battery, then go ahead and plug in the dc jack. First sign it works is the ?Battery charging? light turns on and you know you have a successful replacement. Another final test is to power down the unit, remove the battery, and see if the unit powers on with just the power cord.

At this point you can turn on the laptop and your job is complete. If your laptop doesn?t turn on .. well.. go back to step 4 and 5 and go from there. It can happen, but we haven?t seen it too often unless there are more problems with the laptop than originally thought.

Click here for the picture tutorial



How to Choose a LCD Screen Monitor ?


  • What size to buy? 17" or 19" or 20" or 22" or 24"+ ??? There is an easy answer, the largest monitor will provide you with the best experience. However, you have to consider your desk space, will it fit? Also, if you have a weak video card, new native resolution the bigger monitor provides might make your games a slide-show experience (the games will run fine at non-native resolution but will not look as sharp). If you are a gamer, make sure your video card is fast enough to play at the native resolution of the new LCD for more enjoyment. It is not a bad idea to upgrade your video card with a purchase of a new monitor to run at new resolutions smoothly.

     
  • Nowadays TVs can work very well as monitors, especially the LCD kind. Therefore, your monitor size can be anything from 26", 37", 40", 42", 47", 50", 62", 65" and up. Most TVs can accept VGA, DVI, or simply HDMI connections. The HDMI connection can be run from DVI video card with a cheap adapter into HDMI.

     
  • What is a native resolution? Native resolution is the physical count of pixels on the monitor. Other resolutions become scaled to fit the physical pixels and it results in a more washed out and blurred image. Thus, on LCDs it is the best to run your display in native resolution for best image quality (sharper, more colorful). Usually, the native resolution is simply stated in the description of the item.

     
  • Widescreen 16:10 or 4:3 (square ratio)? It is more of a personal preference. Widescreen allows you to watch new widescreen movies without black bars. Thus, widescreens are majorly used for multimedia purposes. The square ratio kind is best to use in the office, unless you do Excel, the widescreen will not be of much use over the 4:3 ratio. If you are a gamer, note that older games will not work well with widescreen resolutions and the image might be horizontally stretched (depending on abilities of a monitor circuitry to provide 1:1 mapping). Also, take a note that older (2006 and older) video cards were not made to support widescreens and you might need a new video card to take advantage of new widescreen resolutions. However, one of the positive sides in wide screen resolution is that some premium LCD brands even have a physical rotation feature built in the stands of their monitors, it allows to rotate the screen 90 degrees to show webpages and word documents in their entirety naturally like on a page of a paper.

     
  • Most monitors on the back have screw holes compatible with VESA standard to allow use of thousand different mounting systems. Such mounting systems remove a need for a base of a monitor (the base usually can be removed) and support a monitor in a variety of ways. Most popular is an arm extension type of support that affixes to a table and allows to manipulate a monitor on all three axis. Other mounting systems can hold two or more monitors to produce and array of screens, usually used in advertisement, medical, and finance industries. Yet, nowadays the mounts are not priced only for the business, many home users rotate their widescreen monitors horizontally to view webpages in a more convenient manner with VESA compatible stands. Almost all recent ATI or nVidia chipsets allow to rotate the desktop or fit the image on any custom resolution. The VESA on the back of the monitors may come in 2 sizes, 90x90 and 100x100. Most stands come with adapters to fit any of these sizes.

     
  • DVI (digital) or VGA (analog)? This is an easy decision, it simply depends on what your video card supports. Analog is for the older and cheaper cards but DVI is strongly overtakes today's market share. Therefore, before buying a monitor for a VGA connection consider updating your video card to have an ability to utilize a DVI connector and buy a monitor with DVI connection. The DVI is a much better choice than VGA analog, it gives a more stable picture (no shaking) with more accurate and vivid colors, plus, no ghosting is produced. Analog VGA wire is subject to magnetic interference to a much higher degree than DVI. Thus, it is recommended to have a DVI setup to see colors as they were meant to. The larger monitors have higher native resolution and DVI often is the only choice to supply the needed bandwidth. The most cheap monitors still feature only VGA connector while next step up models have both DVI and VGA connectors for most compatibility. Be warned that value monitors often do not include a VGA or DVI cable to appear cheaper in price. Note that DVI video cards can be also connected to TVs or monitors with HDMI inputs using a few dollars adapter.

     
  • Depending on your DVI video card, you might be able to convert DVI signal to VGA with a very cheap adapter. If your video card has DVI-I then it carries in addition an analog signal which can be fed to VGA connector and run a monitor with only available VGA connection. On performance video cards it is somewhat likely that the DVI connector is DVI-D and is only digital without any analog signal added. Such cards are thought to be utilized only on expensive monitors with full DVI capability. It is rather not easy to find out if your card is DVI-I or DVI-D by physical inspection.

     
  • If you are using a VGA interface, please make sure you are using a quality cable. Many low grade or abused cables make a picture much worse than it should be. Common visual artifacts are a shift in color, blur, pulsating or a shaking picture. The cable is usually not included with value monitors to keep prices down. Be sure to have one on hands or to order a new cable.

     
  • The latest input for the monitors is a Display Port. It is a cheap, license free alternative to its more costly HDMI cousin with a few advantages over DVI. For now the Display Port is featured in the most new and ultra expensive screens and is expected to be the next popular standard for computer monitors.

     
  • What else to look for when purchasing an LCD monitor? Well, a contrast ratio is one thing. 700:1 (seven hundred to one) or higher will give you much better blacks and vivid colors than 400:1 ratio. Also note, more expensive monitor with 500:1 ratio might actually give you a better image than a cheaper one with 700:1 (inflated and unsubstantiated ratio). A contrast ratio tells you black are the black colors on the monitor. Many cheap monitors have the most black colors of about dark gray color, these are the ones with lower contrast ratio and on them a picture seems washed out due to inability to represent sharpness well (which is an optical illusion of contrast between light and dark shades). It is also advisable to purchase premium brands for outmost satisfying picture quality and long life.

     
  • There is a growing trend, a technology that offers dynamic contrast ratios in monitors. Be ware of this one since it is a mostly a marketing scheme to show a blown up number for contrast ratio than the monitor can physically deliver. A dynamic contrast ratio tries to fool a human eye into seeing more contrast but it only barely works when watching movies. Overall, it is gives no useful advantage, thus, be careful when comparing contrast ratio numbers between a monitor that supports a dynamic contrast ratio and the one that doesn't. Higher number in this case does not make it better.

     
  • Moreover, a response rate in milliseconds is an important feature if you are a gamer. When first LCD monitors came out, their response time was about 24ms. Scrolling or gaming, even fast movie scenes could trigger blurring ghosting effect. However, nowadays this is eliminated with most monitors manufactured today have 8ms or even quicker response time that no longer produces the undesired motion blur effect. Gaming monitors nowadays advertise 2 or 3 ms response time, cheaper brands overclock their LCD response times, such a practice may cause artifacts to appear on a screen during fast movements of a picture as a result. Therefore, we recommend premium brands for gaming use.

     
  • A viewing angle is the maximum angle a display can be viewed at with an acceptable visual performance. If you are standing directly before the monitor and looking right in the center, you witness the best picture. However, if you are to move either way sideways, you would see that the image becomes darker and at some point even it inverts the colors... The LCD technology is not perfect and does suffer from viewing angle problem where any viewing at an angle gives you a worse picture depending how far you have deviated from the center. How badly the viewing angle can affect can differ from horizontal and vertical angles of the same screen.

     
  • Damaged pixels: More premium brands also have a lesser degree of damaged pixels on their panels than cheaper brands that have lesser quality control. During manufacturing some low percentage of LCD screens come with one or a few pixels that do not light up or are stuck with a specific color. While the manufacturers could in fact throw away these marked screens, they would be operating at a loss. Thus, the damaged pixels now is standard in LCD market until the manufacturing method improves or another technology will overtake LCD. When you buy an LCD monitor there is a low chance (1-2%) that your monitor will have any kind of damage pixels. The dead pixels are less visible since they are simply black but stuck (colored) pixels are most visible on black backgrounds and are a sore during movie watching. Unfortunately, the manufacturers have their own rules on how many damaged pixels is too excessive to warrant a replacement. Fortunately, Directron.com offers a service which gives you a perfect screen.

     
  • As a rule, speakers on LCD monitors never provide a good enough sound due to their small size (bass gets mostly left out). It is recommended to buy a separate stand-alone set of speakers with a subwoofer for a fuller sound. Any cheap stand-alone set of speakers will sound better than monitor built-in speakers in most cases. The monitors that don't feature speakers have a more attractive thinner bezel. Some larger monitors may even feature a USB hub to bring connection closer for such devices as input, webcameras, and sound.

     
  • Probably it has gone mostly unnoticed but the beige color is no longer popular or produced. There are only black and silver (or combination of) monitors available on the market now. These colors do not turn yellow overtime and are simply more stylish. If you are using your monitor mostly in dark environment then it would be advisable to buy a black frame LCD for lesser distractions through the possible reflections on the silver frames.

     
  • There is a new technology in LCDs monitors. It is a special back lighting that is using LEDs. Overall, this new technology allows for better contrast, truer and wider range of colors, plus monitors require less energy to operate. In addition, it is believed that this new LED backlight will help avoid current common backlight failures that are a result of the current cold cathode fluorescent lamp technology.

     
  • The power supply is the most common culprit for failing monitors. During early days of LCD market the LCD monitors were coming with external power supply and all it took is a new "power brick" to heal your monitor. Nowadays the power supply is internal and because of this the LCD monitors are more often discarded and dangerous chemicals are poisoning the landfills. If you are an environment conscious person, LCDs are two fold. While needing much less energy to operate, the LCD screen is poisonous and there are only a few places that truly recycle LCD screens. Please, do recycle your old LCDs properly.

     
  • LCD monitors are EXTREMELY easy to scratch verses their older CRT counterparts, plastic vs. glass. Do take care when moving or wiping your new LCD monitors. Do not use any solvents or alcohol based cleaning solutions since they may permanently react with the screen.

     
  • Why there is such a price difference among monitors? For one, it is the quality of the monitor plus any included support, warranty. There are different grades of LCD panels: A-B-C-lower. The cheaper the monitor, lesser grade LCD panel is used, shorter the warranty is offered. Higher grade LCD panels are more sharp, brighter colors, no bleeding (mixing) of neighboring colors, quicker response, truer whites and blacks that make up contrast, a solid non-shaking picture, no pulsating colors, no bshift in color presentation. It is remotely possible that low grade panels may negatively affect your vision if used for an extended amount of time. That is why we recommend to invest additional $20-$50 for a more quality monitor, in the end personal health matters.
     
  • What are the different LCD screen sizes for laptop and tablet PC computers?

    Laptop and tablet PC screens range in size from 10.4 inches to 17.1 inches. The size is measured diagonally based on the viewable area of the screen. Laptops may come in the following LCD screen sizes: 10.4 inches, 10.6 inches, 11.3 inches, 12.1 inches, 13.0 inches, 13.3 inches, 14.1 inches, 15.0 inches, 15.2 inches, 15.4 inches, 15.7 inches, 16.0 inches, 16.1 inches and 17.1 inches.

    ScreenTek considers devices with LCD screens smaller than 10.4 inches to be PDAs. ScreenTek does not carry LCD screens for PDAs.

    What is LCD screen resolution? And, what are the different LCD screen resolutions for laptop and tablet PC computers?

    Laptop and tablet PC computers come in many different resolutions. Resolution is defined as the number of pixels or small dots that make up an LCD screen. The pixel is the smallest unit that makes up an image. Most screens sold today are TFT active matrix LCD screens. TFT active matrix is a technology in which each pixel has a transistor attached to it to control the backlight shining through it. Each pixel is made up of 3 sub-pixels (red, green and blue) with each having its own transistor. Each of these pixels turns on and off and filters light through colored sub-pixels which results in an image. The more pixels or higher the resolution a screen is the crisper the image. In addition, higher resolution screens allow more of an image to be viewable.

    The following table shows the LCD screen resolutions available in laptops and tablet PCs.

    Resolution Pixels Aspect Ratio Type of Ratio
    SVGA 800 x 600 1.33x Standard
    XGA 1024 x 768 1.33x Standard
    WXGA 1152 x 768 1.50x Wide
    WXGA 1280 x 768 1.66x Wide
    WXGA 1280 x 800 1.60x Wide
    WSXGA 1280 x 854 1.50x Wide
    SXGA 1280 x 960 1.33x Standard
    SXGA 1280 x 1024 1.25x Standard
    WXGA+ 1440 x 900 1.60x Wide
    SXGA+ 1400 x 1050 1.33x Standard
    WSXGA+ 1680 x 1050 1.60x Wide
    UXGA 1600 x 1200 1.33x Standard
    WUXGA 1920 x 1200 1.60x Wide
    QXGA 2048 x 1536 1.33x Standard

    As can be seen in the table above, LCD screens are considered either standard-aspect or wide-aspect. Wide-aspect ratio screens which have become quite popular recently are LCD screens with a resolution aspect ratio greater than 1.33x (number of horizontal pixels / number of vertical pixels).

    What is the relationship between size and resolution?

    Basically, the larger the LCD screen the higher the potential resolution. LCD screens are stated at their maximum resolution which may be adjusted downwards should you need to. Each LCD screen size may come in different maximum resolutions. See the table below for screen size and potential resolution combinations.

    Size Available Resolutions Aspect
    800
    x
    600
    1024
    x
    768
    1152
    x
    768
    1280
    x
    768
    1280
    x
    800
    1280
    x
    854
    1280
    x
    1024
    1440
    x
    900
    1400
    x
    1050
    1680
    x
    1050
    1600
    x
    1200
    1920
    x
    1200
    2048
    x
    1536
    10.4 x x                       Standard
    10.6       x x                 Wide
    12.1 x x   x(a)         x         Standard
    13.0 x                         Standard
    13.3   x                       Standard
    14.0       x                   Wide
    14.1   x             x   x     Standard
    15.0   x             x   x   x Standard
    15.2     x     x               Wide
    15.4         x   x(b)     x   x   Wide
    15.7             x             Standard
    16.0             x             Standard
    16.1                 x   x     Standard
    17.1               x   x   x   Wide

    Notes:

    (a) wide-aspect ratio LCD screen.
    (b) standard-aspect ratio LCD screen.

     


    Can I upgrade the size or resolution of my laptop LCD screen?

    Screen size cannot be upgraded. Your laptop resolution may be upgraded sometimes depending on the type of video card contained in your laptop and if there exists a compatible LCD screen of a higher resolution. We generally discourage against upgrading resolutions as it is not easy to determine a compatible LCD screen between resolutions.

    Do I need a new laptop LCD screen if I have lines on my screen?

    It is possible that you need a new laptop LCD screen. The presence of lines could indicate a problem with the screen, the video cable or the video card.

    Are some laptop LCD screens compatible with other LCD screens?

    Yes. Laptop LCD screens may be compatible with other laptop LCD screens. Moreover, laptop makers like Dell, HP Compaq, IBM, Toshiba and Sony may source more than one LCD screen (as distinguished by the LCD screen's part number) even from different brand LCD screen manufacturers to install in the same laptop model. There are many variables to take into consideration like various physical constraints, electronic signaling characteristics and power issues.

    Do I need a new laptop LCD screen if my LCD screen is dim?

    You may or may not need a new LCD screen if the LCD screen is dim. If your LCD screen is dim it may be as a result of either 1) a faulty backlight or 2) a faulty inverter. The backlight is basically the light bulb in the laptop LCD screen which as one would suspect has an average useful life. The inverter, though, is a separate piece from the LCD screen. The inverter essentially 1) takes the DC power which the laptop runs off of and converts it into AC power and 2) steps-up the voltage to light up the cold cathode fluorescent backlight.

    We have found that when a laptop LCD screen is dim the majority of the time it is a result of a faulty inverter (especially for HP laptop components). Unfortunately, the best way to determine which is the cause of the dim screen is through process of elimination by trying either a new LCD screen or a new inverter and seeing which solves the problem. We highly recommend you purchase an inverter first as inverters are less expensive than LCD screens. ScreenTek does not carry inverters, however, we would be more than happy to refer you somewhere.


    What are the differences in notebook screen part number suffixes?

    A part number suffix is an extension of the notebook screen part number used to identify some minor differences between a notebook screen with a similar part number. See the table below for examples of suffixes for different notebook screen manufacturers.

    LCD Manufacturer LCD Part Number LCD Part Number Base LCD Part Number Suffix
    Samsung LTN141X8-L00 LTN141X8 L00
    Samsung LTN141X8-L02 LTN141X8 L02
    LG Philips LP141X14 (A1) LP141X14 A1
    LG Philips LP141X14 (B1) LP141X14 B1
    Hitachi TX38D85VC1CAA TX38D85VC1 CAA
    Hitachi TX38D85VC1CAB TX38D85VC1 CAB

    Notebook screens with the same base part number, but different suffix are the same screen. The suffixes distinguish a different manufacturing batch for a particular base part number. A part number with a different suffix commonly denotes superficial and negligible differences between notebook screens. These superficial differences may include differences in inverter cable length or serve as an identification method to distinguish between batches of LCD screens for different notebook brands. For example, the LTN141X8-L00 is installed in an IBM ThinkPad and the LTN141X8-L02 is installed in a Dell Inspiron 4000.

    Be aware that there are some exceptions in which the suffixes denote more profound differences between similar part number screens.


    Windows XP HELP/TIPS

  • Windows key + R = Run menu


  •    cmd = Command Prompt
       iexplore + "web address" = Internet Explorer
       compmgmt.msc = Computer Management

  • Windows key + E = Explorer


  •    ALT + Tab = Switch between windows
       ALT, Space, X = Maximize window
       CTRL + Shift + Esc = Task Manager
       Windows key + Break = System properties
       Windows key + F = Search
       Windows key + D = Hide/Display all windows
       CTRL + C = copy
       CTRL + X = cut
       CTRL + V = paste

  • Keyboard Shortcuts


  •    [Alt] and [Esc] Switch between running applications
       [Alt] and letter Select menu item by underlined letter
       [Ctrl] and [Esc] Open Program Menu
       [Ctrl] and [F4] Close active document or group windows (does not work with some applications)
       [Alt] and [F4] Quit active application or close current window
       Ctrl] Lft., Rt. arrow Move cursor forward or back one word
       Ctrl] Up, Down arrow Move cursor forward or back one paragraph
       [F1] Open Help for active application
       Windows+M Minimize all open windows
       Shift+Windows+M Undo minimize all open windows
       Windows+F1 Open Windows Help
       Windows+Tab Cycle through the Taskbar buttons
       Windows+Break Open the System Properties dialog box
       explorer shortcuts
       END....... Display the bottom of the active window.
       HOME....... Display the top of the active window.
     
  • Type the following commands in your Run Box (Windows Key + R) or Start Run


  •    devmgmt.msc = Device Manager
       msinfo32 = System Information
       cleanmgr = Disk Cleanup
       ntbackup = Backup or Restore Wizard (Windows Backup Utility)
       excel = Microsoft Excel (If Installed)
       msaccess = Microsoft Access (If Installed)
       powerpnt = Microsoft PowerPoint (If Installed)
       winword = Microsoft Word (If Installed)
       frontpg = Microsoft FrontPage (If Installed)
       notepad = Notepad
       wordpad = WordPad
       calc = Calculator
       mspaint = Microsoft Paint
       wmplayer = Windows Media Player
       control = Opens the Control Panel


  • Internetbrowser


  •    type in u're adress "google", then press [Right CTRL] and [Enter]
       add www. and .com to word and go to it


  • For Windows XP:

  •    Copy. CTRL+C
       Cut. CTRL+X
       Paste. CTRL+V
       Undo. CTRL+Z
       Delete. DELETE
       Delete selected item permanently without placing the item in the Recycle Bin. SHIFT+DELETE
       Copy selected item. CTRL while dragging an item
       Rename selected item. F2
       Move the insertion point to the beginning of the previous paragraph. CTRL+UP
       Select all. CTRL+A
       Search for a file or folder. F3
       View properties for the selected item. ALT+ENTER
       Close the active item, or quit the active program. ALT+F4
       Opens the shortcut menu for the active window. ALT+SPACEBAR
       Close the active document in programs that allow you to have multiple documents open simultaneously. CTRL+F4
       Refresh the active window. F5
       Cancel the current task. ESC [TOP]

     

    General Preventive Maintenance Of Laptop

  • Don't leave your battery unused for long periods of time. Even if you use AC power most of the time, use the battery regularly to       keep it in good condition. Switch off your AC adapter when the laptop is not in use. This prevents overcharging.

  • To extend battery life, you can try decreasing the LCD brightness while using your notebook. You can activate the `Standby' and       `Hibernation' power­ saving modes, too, for better battery life, you can put off the Wi-Fi when not in use.

  • If you do not use your laptop for extended periods of time-a week or more ­remove the battery pack from the laptop, but only after       discharging it fully.

  • No eating and drink­ing near or around your laptop. The least bit of water could short-circuit some sensitive laptop circuits, and       render it useless.

  • You may sometimes be tempted to turn your laptop off by simply holding down the power button until it powers down. Although       quick, this method is harmful to the laptop and could cause data loss. A hard reboot should only be used as a last resort.       Sometimes this is inevitable, for instance, when Windows hangs. But this should not be a regular practice.

  • Don't subject your laptop to jerks and shocks. This will help avoid damage to your hard drive. Preferably, power the notebook off       before moving it from one place to another.

  • External peripherals and accessories such as external opti­cal drives, PC cards and USB keyboard lights draw power from the       notebook. Disconnect such devices when not in use.

  • Booting the notebook when it is not connected to a power source draws a lot of power from the battery. Instead of shutting down       your laptop in the middle of a meeting, choose the `Suspend' mode if you wish to use it again after just a short interval. This will       save battery and help you restart your work faster.

  • If you have just shut down your laptop, give it 30 seconds before you start it up again. This ensures that the hard drive has spun       down, and is not subjected to sudden switching on and off.

  • Don’t put on the laptop keeping of cloth or bed because generally the air flow is  from bottom, regular doing so may reduce the life       of laptop circuit.

  • Don’t press very hard the laptop keyboard because, if damaged can cost very high, therefore while playing game use external       keyboard.[TOP]
  • Guide To Purchase Used Laptop

  • Laptop is used to carry from place to place…so people who travel a lot must think of the weight of the laptop.

  • Every battery has a lifetime. So going for a Laptop with hardly any battery backup is not suggested. Minimum of 45 minutes battery      backup is very necessary. So while purchasing the secondhand laptop please keep in mind to check the laptop only on battery for      minimum 30 minutes and also keep an eye on battery usage indicator.

  • Carry with yourself an audio, video & Blank CD/DVD so that u can check the audio section and video section of the laptop      including the CD/DVD read/write test.

  • Run the scandisk utility available in all versions of windows and check for bad sector in hard disk.

  • Take with yourself any external device like thumb drive to test the USB port.

  • Take with yourself SD memory card to test Card Reader (If the option is available on the laptop)

  • Take any good floppy to test the floppy drive (Any how current Laptops are not coming with Floppy Drive)

  • Take an external headphone and microphone to test the external audio port.

  • Attach the laptop to the external monitor to check the external VGA port is working or not.

  • Open any word file and check all the keys are working or not.

  • Check for battery charging for 5 to 10 minutes and see the battery indicator is showing charging.

  • Press the window and the break keys on the keyboard and see the amount of RAM and CPU details. Further check the hardware      and then the Device manager to see all driver are installed or not. There should be no Exclamation mark.

  • Slide the LCD screen slowly on the hinges and check any flicker on the display if so there may be a problem on the connector      cable driving the LCD circuit of the laptop.

  • Also check the Modem, Bluetooth & Wi-Fi Port if available on your laptop to be purchased (Do only if you know) I will be writing on    these subject next.

  • Check the laptop minimum for 45 minutes to see whether laptop hangs or restarts or shutdowns.

  • See the Laptop User manual and Driver CD are there with the Laptop.

  • See that u get a laptop carry case, otherwise u have to purchase one.

  • If all the conditions meets out OK and within your budget just go for it.