Geforce Go 6800U Component (Pic)

[JohnB]

I have a question on an older video card - My old Dell XPS Gen2 laptop has a GeForce Go6800 Ultra card that's been giving me trouble lately. I've tried the 'oven trick' to re-flow the solder, but that only allows the card to work for a very short period of time.

I'm trying to identify the following components on the board because they run extremely hot, and I think replacing them might allow it to function properly. Would anyone know what these particular components are? They're labeled as L1 & L2 on the board and have "R56 C081" on them.

Thanks for your help.
-John

 

[keenan]

They are inductors used in the switch mode power supply. Some heating is expected; excessive heating probably indicates a problem, but it's unlikely to be with the inductors themselves.

The value is 0.56μH (560nH). This might be a suitable replacement, but do measure the existing inductors as it's hard to tell from the picture what size they are: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=513-1374-1-ND

Though like I say, it's pretty unlikely these are the problem.

 

[JohnB]

They are inductors used in the switch mode power supply. Some heating is expected; excessive heating probably indicates a problem, but it's unlikely to be with the inductors themselves.

The value is 0.56μH (560nH). This might be a suitable replacement, but do measure the existing inductors as it's hard to tell from the picture what size they are: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=513-1374-1-ND

Though like I say, it's pretty unlikely these are the problem.

Thanks for the response Keenan. It would be nice to have a schematic of the board to work with, but I doubt I'd be able to find one. I won't hold you to it, but, if not the inductors themselves, would you suspect the capacitors that are nearby? Or another component? This particular 6800 acts the same way on two different motherboards, so I don't think it's from the mobo. There are components on the board, directly opposite the inductors that I think can't handle the heat being generated, and the card refuses to operate at that point.

 

[keenan]

Those look like they're the MOSFET switches in the power supply. I'd also expect these to get warm-to-hot, if they're directly on the other side from the inductors, they're probably what's generating the heat that makes inductors to feel warm. Not necessarily a problem either, and without a schematic it's going to be tricky to find test points and what voltages they should be at to check out the power supply's operation. The problem here is that plenty of failures downstream from the power supply will make it feel warmer than usual, but that tells you nothing about where the problem actually is, and without a working reference board it's hard to know if that heating is normal or excessive.

If it's not a generic recap-burst-electrolytic caps repair, it's going to be hard to track down, it could easily just be a failed GPU, but there's no way to know without expensive high end tools and schematics and datasheets, which you're just not going to get.