Hello, I had my PC fail to boot and deduced that there was a short on the 12V rail of my GPU causing the PSU to shut down. I watched this video and found that I had a similar looking problem, measured 4.9K on Pin 1 (high side gate) of all the MOSFETs apart from one, which showed 0.3 Ohms just like when I measured at the PCIE power connector.
The MOSFETs on my card are these: https://www.farnell.com/datasheets/2140526.pdf
I replaced the part with this: https://www.mouser.co.uk/datasheet/2/196/Infineon-BSG0811ND-DS-v02_02-EN-1226290.pdf
When I removed the original part the short disappeared, and it didn't return when I fitted the replacement, looking good, I thought.
Well, I plugged it back into my PC and it presented exactly the same failure that it did originally. I removed the card again, measured it, and the new MOSFET has failed exactly the same way the original one had.
I dropped a comment on the AHOC video for my card, and Buildzoid reckons the gate driver might be the culprit, which makes sense. Measurement agrees, I'm seeing 1.3 to 1.5 Meg on pin 1 of the rest of them, and 5K on the suspect one.
www.youtube.com/watch?v=RmLghOdd8V0
I can't read the part number on the gate drivers I have, but I have found forum posts from someone else who has read "DU F526" on theirs and is looking (unsuccesfully) for a replacement. Failing that, I'd need to figure out a suitable set of specs myself but I'm not quite sure where to start. I suppose I'll need a voltage rating comfortably higher than 12, an output voltage that's higher than the MOSFET threshold, and fairly short rise and fall times (how short matters?). They are 8 pin devices, square, about 2mm on each side.
So after all that, is there anything else I should check to minimise the chance that it just does the same failure again?
Thanks,
Chris
The MOSFETs on my card are these: https://www.farnell.com/datasheets/2140526.pdf
I replaced the part with this: https://www.mouser.co.uk/datasheet/2/196/Infineon-BSG0811ND-DS-v02_02-EN-1226290.pdf
When I removed the original part the short disappeared, and it didn't return when I fitted the replacement, looking good, I thought.
Well, I plugged it back into my PC and it presented exactly the same failure that it did originally. I removed the card again, measured it, and the new MOSFET has failed exactly the same way the original one had.
I dropped a comment on the AHOC video for my card, and Buildzoid reckons the gate driver might be the culprit, which makes sense. Measurement agrees, I'm seeing 1.3 to 1.5 Meg on pin 1 of the rest of them, and 5K on the suspect one.
www.youtube.com/watch?v=RmLghOdd8V0
I can't read the part number on the gate drivers I have, but I have found forum posts from someone else who has read "DU F526" on theirs and is looking (unsuccesfully) for a replacement. Failing that, I'd need to figure out a suitable set of specs myself but I'm not quite sure where to start. I suppose I'll need a voltage rating comfortably higher than 12, an output voltage that's higher than the MOSFET threshold, and fairly short rise and fall times (how short matters?). They are 8 pin devices, square, about 2mm on each side.
So after all that, is there anything else I should check to minimise the chance that it just does the same failure again?
Thanks,
Chris