Help with computer motherboard repair?

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silviasol

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Dec 30, 2012
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I have this motherboard from a all in one computer. It had a power surge and now has no power. It will receive power and a motherboard led light comes on but will not boot or show the normal power led light at the power button. It is kind of a desktop hybrid laptop computer, dell inspiron one (all in one computer). Anyways I know that the small components like sop8 chips are common to fail in power surges and have fixed other laptop motherboards that I have been told which chip is the most common to fail, I just don't know this one. Probably a long shot but was hoping someone might know or provide some kind of incite.

I have photo's of the board.
http://i928.photobucket.com/albums/ad124/chips2482/IMG_1038.jpg

http://i928.photobucket.com/albums/ad124/chips2482/IMG_1039.jpg
 
look for a TVS transient voltage suppressor on the input from the power jack. it is like a fuse and diode together so that if the input voltage is really high it blows the fuse and opens the circuit. but if you have an led it must be intact still unless the TVS is beyond the led which doesn't seem likely. is it possible the cold cathode driver is bad now or the tube burned up in the transient? can you check with a monitor to see if there is a display?
 
So then, first things first the power supply is good or you have substituted with a known good unit and it behaved the same?
 
dnmun said:
look for a TVS transient voltage suppressor on the input from the power jack. it is like a fuse and diode together so that if the input voltage is really high it blows the fuse and opens the circuit. but if you have an led it must be intact still unless the TVS is beyond the led which doesn't seem likely. is it possible the cold cathode driver is bad now or the tube burned up in the transient? can you check with a monitor to see if there is a display?
Click to expand...

The led is like a computer motherboard led showing that it is receiving power. When the power adapter is plugged in, it uses a laptop power adapter, that light comes on but the power button light is suppose to come on and stay amber color then blue when it is running. When I plug it in the power button light blinks once and will not power on, there also is a small pop in the speakers which I think is normal even on a working unit. I try to search the numbers on the chips but nothing comes up about what they are. For sure there is no video, the fan would run if it would show some kind of power. No heat from the cpu or onboard gpu either.

led
http://i928.photobucket.com/albums/ad124/chips2482/IMG_0831.jpg~original

close up of the board near the jack
http://i928.photobucket.com/albums/ad124/chips2482/IMG_1040.jpg~original
http://i928.photobucket.com/albums/ad124/chips2482/IMG_1042.jpg~original

biohazardman said:
So then, first things first the power supply is good or you have substituted with a known good unit and it behaved the same?
Click to expand...

Yes the power supply is reading 19.5v and I tried with another that I have and still nothing.
 
It could be your memory modules which would mean you would need a new mother board. I think you can get memory modules repaired but it'd be super expensive. I mention this because something similar happened to my mother board on a computer I owned a few years ago.
 
Sorry missed your reply. Many motherboards require the CPU fan to be hooked up they won't stay powered up as doing so even for a short time without a CPU cooler will toast many CPUs. Were it me I would put the cooler on, hook up the fan ,a keyboard and a video screen of some sort. Then see if it will do anything at all. Some systems require memory to even boot into bios. If it still won't boot with those minimal devices hooked up then I can't help.
 
did you try to power up the board itself from the AC adapter? the power supply for the board is not the AC adapter. on the motherboard there is gonna be a set of capacitors and voltage regulators to establish power to the individual current busses. should find 5V and 3.3V too imo.
 
silviasol said:
Yes the power supply is reading 19.5v and I tried with another that I have and still nothing.
Click to expand...
If that wall unit is still working normally, I would not expect that it could have gotten any power surge past it into the system itself. Usually the wall unit would be damaged first, as it usually has some internal protections itself, to prevent damage to it from surges/brownouts, and to prevent passing that damage on to whatever it is powering.

But if the systme doesn't work with evne a second known-good unit, *something* happened.

Was there any other wall-powered device plugged into the system when the surge happened? I ask because perhaps if that device also no longer works, perhaps the surge entered via that device, which might tell you where to start.

One thing about the full-board image: there is a chip with a dark "smudge" across it's lower left corner, starting at the corner of the silicon die itself. Is that just a smudge that looks dark because of camera angle/etc, or is it a burn mark?
 
amberwolf said:
silviasol said:
Yes the power supply is reading 19.5v and I tried with another that I have and still nothing.
Click to expand...
If that wall unit is still working normally, I would not expect that it could have gotten any power surge past it into the system itself. Usually the wall unit would be damaged first, as it usually has some internal protections itself, to prevent damage to it from surges/brownouts, and to prevent passing that damage on to whatever it is powering.

But if the systme doesn't work with evne a second known-good unit, *something* happened.

Was there any other wall-powered device plugged into the system when the surge happened? I ask because perhaps if that device also no longer works, perhaps the surge entered via that device, which might tell you where to start.

One thing about the full-board image: there is a chip with a dark "smudge" across it's lower left corner, starting at the corner of the silicon die itself. Is that just a smudge that looks dark because of camera angle/etc, or is it a burn mark?
Click to expand...


I am just assuming it was a surge because the other laptops I have had with burnt sop8 chips the ac adapters were fine also. About 90% of these boards had no visible burn marks on the chips they were just always sending power thru them which caused something to not allow power to the board, I would know right away because I could test the chip on ohm setting. I did check all chips for burn marks and they look fine. I would assume since this is a laptop they have extra circuitry to keep any kind of smoke/burning from happening as I have rarely seen burnt components on laptop motherboards in the 5 years I have sold laptop parts on ebay.

I am giving up on repairing it though. I bought the laptop thinking it had the common bga gpu issue which I have rework equipment to install new gpu chips. It is a very rare board to find without purchasing the entire laptop, dell inspiron one, but I had seen motherboards in the past so will have to just keep searching until I find one and hope it has power just has the common bga issue.
 
i tried replacing the cold cathode tube on my dell laptop screen and it never worked after that. i think i damaged the screen perimeter traces for the arrays while handling it.

i woulda never ever have attempted it before i started using this place to teach myself electronics again.

i just took apart a flat screen tv and tried to figure out why the screen did not power up.

after just going through the wiring harnesses and reconnecting them it started working again even though i had not found anything wrong while testing so i just put it back together and plugged it in to check voltages off the power supply.

works just like new, minus a few pieces of plastic trim that came off when i was opening it.

neat to see you doing this. really really wish i could get girls to do it more. a friend just got the chance to be the sound manager for the public radio broadcast of the portland blues festival this summer. she was the first woman to pull it out of all these years at kboo, and was on top of the world. so cool. in another EV ancillary, met her when i ran outa juice on my first long range test of my ZENN car. "hi, do you mind if i plug my charger into your duplex outlet? sure, no problem, want some coffee?" you gotta love portland.
 
dnmun said:
i tried replacing the cold cathode tube on my dell laptop screen and it never worked after that. i think i damaged the screen perimeter traces for the arrays while handling it.

i woulda never ever have attempted it before i started using this place to teach myself electronics again.

i just took apart a flat screen tv and tried to figure out why the screen did not power up.

after just going through the wiring harnesses and reconnecting them it started working again even though i had not found anything wrong while testing so i just put it back together and plugged it in to check voltages off the power supply.

works just like new, minus a few pieces of plastic trim that came off when i was opening it.

neat to see you doing this. really really wish i could get girls to do it more. a friend just got the chance to be the sound manager for the public radio broadcast of the portland blues festival this summer. she was the first woman to pull it out of all these years at kboo, and was on top of the world. so cool. in another EV ancillary, met her when i ran outa juice on my first long range test of my ZENN car. "hi, do you mind if i plug my charger into your duplex outlet? sure, no problem, want some coffee?" you gotta love portland.
Click to expand...

Yes replacing the ccd is tricky. I have done a few with success, the first few were hit and miss. On my successful ones I would cut the metal rim to open it easier then cut even more of the plastic to keep from having to remove the screen which WILL get dust in it no matter how clean your room is. I gave up later because it takes too much time, just started buyign screens.

On the flat screens many times it is just a cold solder joint. You can search youtube and many of the common ones will have guides to which component needs resoldering. Many times with cold solder joints just opening and giving the circuit board some kind of bump will temporarily connect the joint.
 
i think that is what i am gonna do. i found a screen for $35 on ebay but i think i will look around here and see if can find the guys who disassemble the ones scrapped by the recycling programs. i think that is how stuff gets to ebay.

my ccd had a bad connection on the very tip of the tube and burned a black spot in the heat shrink and goop.
 
D830, uses 14.5" screen. to take the screen off i need to open the case to get the hinges and ribbon connector. it is still a daunting task for me but i have more and more confidence the more things i take apart. and sometimes can put back together.

my problem is losing parts like screws from the time i open something until i put it back together. i recently took apart a Vpower charger for biohazardman, duane, so i could hack the output voltage down from 60V to 51V. when i go to put the plastic case back on i cannot find all the screws. at least i found enuff to hold it together. hope he doesn't read this. duh.
 
Its often the power supply that dies before the MB, I would look into that first.
That MB looks pretty old, if you live in the USA I would bet you could get a laptop of equiv performance for same price of getting the old one fixed or probably faster.
 
TheBeastie said:
Its often the power supply that dies before the MB, I would look into that first.
That MB looks pretty old, if you live in the USA I would bet you could get a laptop of equiv performance for same price of getting the old one fixed or probably faster.
Click to expand...

No these are cooler then laptops. It is touchscreen. These amd cpu/gpu model boards/computers are really good machines but are very prone to bga failure. 23" screen. It is perfect for next to my bed. A good chance I can fix this $50 motherboard which gives me a rare $400 machine that really is worth more then it's going rate imo.

dell-inspiron-one-2305.jpg


dnmun said:
D830, uses 14.5" screen. to take the screen off i need to open the case to get the hinges and ribbon connector. it is still a daunting task for me but i have more and more confidence the more things i take apart. and sometimes can put back together.

my problem is losing parts like screws from the time i open something until i put it back together. i recently took apart a Vpower charger for biohazardman, duane, so i could hack the output voltage down from 60V to 51V. when i go to put the plastic case back on i cannot find all the screws. at least i found enuff to hold it together. hope he doesn't read this. duh.
Click to expand...

Ok your issue may not be the screen if you get power on no video. Are you getting video from an external monitor? That is another one of the common boards with the gpu bga issue, this is most common on the boards with the nvidia gpu. I can help you fix the motherboard if it is the issue. I have some good repair techniques using only household equipment that pretty much matches bga rework machines worth thousands of dollars.
 
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