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Old 05-30-2021, 10:53 PM   #6
momaka
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Default Re: Tesla m40 burned my motherboard VRM

Probably not the PSU then.

I suspect this was just a "freak" accident - likely something to do with things moving around a bit when the card was installed. For example, I see you have some custom bolt mods going through the board for the CPU heatsink. Even with proper insulating washers under the nuts, you still have to be careful how you install these. The one in the upper-right corner of the first picture looks especially accident-prone with the way the steel washer gets close to SMD components there. If you don't have good thick plastic insulating washer (and make sure they don't apply pressure over any SMD component or near it), then that could well have shorted when the card was inserted and thing were moved a little. As to why the card/board didn't show problems right away but only when you installed the drivers - well, something could have been super-close to shorting from those bolt mods, but just had to "wait" for the "right" moment.

In any case, I don't see why/how the Tesla could short out the CPU VRM. Perhaps maybe due to PCI-E lines on modern CPUs going directly to the PCI-E slots?? But even if that's the case, there are signal coupling caps on those lines, so I think damage should have been prevented.

To be on the safe side, perhaps try the Tesla card in an old (and maybe less valuable) board that doesn't have PCI-E bus lanes from the CPU going directly to the card. Something like socket 775 (Intel) or 939/AM2 (AMD) might be a good test bed. If the card works there and installs the drivers without issues, then I'd say the whole VRM burning thing must have been a coincidence or freak accident. But if not, then you may want to check the Tesla card for any obvious defects (missing/chipped SMDs, shorted ceramic caps on the PCI-E slot used for signal coupling, and etc.)

Last edited by momaka; 05-30-2021 at 10:56 PM..
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