Laptop Motherboard Repair

[TECHMECH]

Re: Laptop Motherboard Repair

Hello, I would check for a short between inductors and ground, then check for a shorted transistor in the power on signal circuit.

[precision001]

Re: Laptop Motherboard Repair

If a mosfet is shorted, would it show zero ohms between all pins? I have another motherboard with no power, and found a mosfet with zero ohms between all of it's pins, so I think it's bad. It's labelled 4825p. I'm going to have to try to find a suitable replacement for that one. I wonder if there is a cross-reference guide of some kind for these. I'm going to do the same check for this DV6000, and check for shorts like you say between inductors and ground. If I detect zero ohms between an inductor and ground, what would be the next logical step?

[precision001]

Re: Laptop Motherboard Repair

I replaced the 4825p mosfets, but the problem remains. One of the mosfets still shows shorted on all pins. I'm not sure where else to look.

[precision001]

Re: Laptop Motherboard Repair

DV6000 No Power - Blue DC Block lights..

Low ohms

181 ohms - 7636 (By 8724)

51 ohms - 7636 (by ENE)

274 ohms - 6679 (opposite side of CPU socket)


Replace all? This version of the board uses an intersil SMPS controller. How would I test it? ISL6236

[TECHMECH]

Re: Laptop Motherboard Repair

I too wish there was a mosfet cross reference guide. So far I have the best luck finding out which manufacture they are and finding the datasheet. Probably best to replace it with the same though. I would check the caps and mosfets near the shorted inductor first. However you may find that it is an IC shorted, then things get tricky, I have trouble with this myself. I would definitely replace that mosfet showing 0 across the board. Do you have any experience with dv6/9000s that power on for about 3 seconds then power off. I have a stack of 10 that are all doing this, no shorts, reflowed, even replaced the NB on a couple. They are the MCP67xx Chips. The one with north and south combined. Im thinking one of the maxim chips or the clock controller? Any suggestions?

[precision001]

Re: Laptop Motherboard Repair

3 seconds then off? Sometimes reballing does the trick. But there are some cases when the gpu has nothing to do with it. I'm still trying to determine that myself.

[momaka]

Re: Laptop Motherboard Repair

I replaced the 4825p mosfets, but the problem remains. One of the mosfets still shows shorted on all pins. I'm not sure where else to look.

Try removing the MOSFET first and then test it for shorts. If it shows none, there is something else shorted on the board.

[precision001]

Re: Laptop Motherboard Repair

The problem is figuring out what that shorted part is. I happen to have an identical board here, that has other issues. I have my new dark infrared station, so I'm going to remove and replace each part, one by one, until (hopefully) I find the bad part. It's gonna suck but, that's how you learn.

[rop12770]

Re: Laptop Motherboard Repair

Hello

Finally after a great search, I have found the FORUM that I need.

I have been reading this post about laptop motherboards and I was very excited with the help that is given.

I work with computer for about 13 years, but not reparing components. I changed the malfunctioning part, but now I'm very interested in solve some problems especially with laptop boards.

I'm very newbie. Can you guys show me the way of troubleshoting?
Where should I start?

Thank You

[precision001]

Re: Laptop Motherboard Repair

Laptop drawing exactly half of normal current before power button pressed. No change after button pressed, no sign of life. What could this be? Bad FET?

[insomnia]

Re: Laptop Motherboard Repair

is there any chart around or link around that shows all different types of smd smt components after looking at this post i was checking the little small 3 legged things but seen a picture of mosfets on a board there in this post and was very surprized any know were i could get to know all the different components

[Heracles]

Re: Laptop Motherboard Repair

Hello!
I have a problem with an Acer 3610 motherboard. There is no video on the LCD, only on an external screen. I have tested with two different sets of LCDs and inverters and they are tested ok with a similar motherboard. If I connect an external screen, even without a keyboard connected, the image is displayed on the external screen after 1 second.

It seems to me that the system checks if the LCD is connected, fails to detect one, and then routes the display to the VGA-port instead. I have tried to drive the inverter with an external source, just to see if the problem is related to the backlight not working, the CCF-lamp lit, but there was no image.
Does anyone have an idea what to check for?
Eric

[infringer]

Re: Laptop Motherboard Repair

This forum is for the discussion and creation of a guide please do not ask people for fixing your laptop in this thread start a new one kindly in the laptop repair forum!

No newbies thread consider this one people are this is a joint deal to make a guide for newbies and everyone if you interrupt it with annoying little please help me fix my <insert whatever here> it may never go no where! Start your own thread!

Back to the guide I think we should make a basic known issues for certain models...

I will start it off...

HP DVxxxx is known for gpu overheating
Acer 3100/5100 is known for south bridge

We should list things in this manner:

Known Issue: 3100/5100 Acer Motherboard

Culprit: South Bridge

Most Common Error Message: Error 200

Conclusion: Laptop booting with error message 200 may need solder work on two chips on the motherboard.

Action: Preform rework with solder iron to fix error 200.

Video: http://www.youtube.com/watch?v=47PdJ5FWsQQ

Preventative Solutions: <Insert your ideas here>

Treat them as a TSB and keep in easily readable formats !!!

Now this is a start to guide creation.

[Pyr0Beast]

Re: Laptop Motherboard Repair

Compaq nc-nw82x0 series (8220, 8230)

It is a POS, overheating garbage.

Southbridge develops a cold joint (under the touchpad) and it is insanely hot.

If you hold southbridge down with your finger it boots just fine.

Preventive solutions: Don't EVER buy it.



Acer aspire 5220 (and similar)

nVidia all in one northbridge develops a cold joint (Separate GPU is OK)

Reflow worked for an hour, then it died completely.



Compaq nw800

Pentium 4 POS
Graphic card (ATI) develops a cold joint and laptop refuses to boot.
If you press down on the middle of the keyboard it will work for some time.

Workstation versions suffered even more often from this problem.


Hp-Compaq n8000 series.
Excellent machines, cold, fast and reliable. Awesome speakers, but screen somehow cracks quite often.

[infringer]

Re: Laptop Motherboard Repair

Known Issue: 3100/5100 Acer Motherboard

Culprit: ATI Chip on top side of motherboard

Most Common Error Message:
Bus:06 Device:02 Function:00 ERROR
Resource Conflict - PCI in slot 03 Bus:06 Device:04 Function:00 through 04 individual messages of course.

Conclusion: All PCI devices run through the south bridge of the motherboard. So looking in this region graphics and PCI devices I found BGA ATI CHIP was cause.

Action: Remove Top half of case. Look for chip marked ATI in big letters. Then get out your heat gun and repair by applying heat to it.

Video: Not Available but similar procedure video here:
http://www.youtube.com/watch?v=ctHTF3oNdxI&NR=1
Warning!!!: NEVER USE COINS TO FIX BGA CHIPS THIS IS NOT SMART AT ALL!!! But the heating principal is the only way to fix a BGA Chip with bad Balls! Unless you have it professionally done!

Results: Seems to work to resolve the issue if done correctly but is very difficult to get it just right it is not as easy as most BGA Jobs! So be warned!

Preventative Solutions: <Insert your ideas here>

[Pyr0Beast]

Re: Laptop Motherboard Repair

Asus A6000

Main chip (next to the cpu) - Sis - develops a cold joint
Laptop does not display a picture when booting, it seldom boots every 10 or more tries.

Preventative Solutions: RMclock and down-volting the cpu thus reducing thermal stress.

Reflow (with lots of preheat) and it should work.

Build quality is quite amazing.

[infringer]

Re: Laptop Motherboard Repair

Nice infro Pyr0Beast! thanks for sharing now we got a nice start to a guide...

Finally in our guides we should include general repair procedures the easy ones like DC Jack replacement, Monitor Replacement, HDD and Ram Replacement, Wireless Card replacement, Cap Testing, Backlight repair.... The more in depth stuff will require a scope and other things that most people cannot afford so lets stay away from things that are too in depth unless they are known problems.

Basic trouble shooting with power and POST error messages should be to apply pressure to chips related to the error mainly south bridge chips it seems then boot and see if the error still appears...

Thanks we still have many postings to go but basically we have a great start!

[retiredcaps]

Re: Laptop Motherboard Repair

Acer aspire 5220 (and similar)

nVidia all in one northbridge develops a cold joint (Separate GPU is OK)

Reflow worked for an hour, then it died completely.

I just received an Acer TravelMate 2450. When the power is presed, the fan spins, the light next to the on/off button and the on/off button is lit, but nothing is displayed on the screen.

I hooked up a known working LCD monitor via VGA and still see nothing. I took out the hard drive, wifi, tried another DRAM chip and still the same symptoms as above.

Are Acer TravelMate's "known" for any type of motherboard/GPU type of issues.

[Uranium-235]

Re: Laptop Motherboard Repair

the whole HP DV series is messed up. I've seen DV 2000's, DV6'S, DV7'S with the same nvidia chip problem. lucky we found this local iranian guy with like schematics for tons of laptop boards that fixes them for $85. he has no sony schematics though

I can fix any caps but this level of stuff I don't touch

[Scenic]

Re: Laptop Motherboard Repair

Sony's are unfixable unless you're able to resolder BGA chips..
most of them (like the VGN-FS215 (or was it 415?) of a friend of mine) just go dead from one day to the other.. Northbridge solder issues..

new board or more like a fixed one costs 100+ bucks.. not worth it for a Pentium M laptop.. even though they're built like a tank.. (most of the case is metal.. not plastic)