Gigabyte RTX 3080 gaming OC Missing 5v

[BougBawi]

I have a RTX 3080 I am attempting to repair. I have lots of micro and SMD soldering experience but lacking in diagnosis knowledge.

Initially the card shut down one day and I found a burnt ceramic capacitor on the 12v rail. Replaced that and another broken cap and it appeared to be working. It worked for another two weeks and then shut down again. Nothing appeared to be burnt this time and 12v was present at both capacitors that were replaced.

Taking measurements I had no 5v rail and it read. 0.2v on that rail at the coil.

Resistance measurements were:
2.5kohms at 5v rail
45ohms at memory
1.6kohms at 1.8 rail
4.5 ohms at PEX
I am taking this from memory as I am not at home atm.

Card would sometimes sporadically have all voltages and display an image then no 5v

It then suddenly blew a VRM mosfet and 12v shorted to ground, blew a fuse. Removed mosfet and short went away. Replaced mosfet and there's no short and I replaced fuse. 5v came back to life briefly and disappeared. Same 0.2v.

I noticed that I only have 1.5v on the 12v pcie line. But there is no short on that line.

 

[BougBawi]

I have a RTX 3080 I am attempting to repair. I have lots of micro and SMD soldering experience but lacking in diagnosis knowledge.

Initially the card shut down one day and I found a burnt ceramic capacitor on the 12v rail. Replaced that and another broken cap and it appeared to be working. It worked for another two weeks and then shut down again. Nothing appeared to be burnt this time and 12v was present at both capacitors that were replaced.

Taking measurements I had no 5v rail and it read. 0.2v on that rail at the coil.

Resistance measurements were:
2.5kohms at 5v rail
45ohms at memory
1.6kohms at 1.8 rail
4.5 ohms at PEX
I am taking this from memory as I am not at home atm.

Card would sometimes sporadically have all voltages and display an image then no 5v

It then suddenly blew a VRM mosfet and 12v shorted to ground, blew a fuse. Removed mosfet and short went away. Replaced mosfet and there's no short and I replaced fuse. 5v came back to life briefly and disappeared. Same 0.2v.

I noticed that I only have 1.5v on the 12v pcie line. But there is no short on that line.

UPDATE: there was a 12v pcie fuse at the back of the card that had a partially burnt leg, seems like some crud or liquid got there for some time and it had worn away at the solder and slightly burnt. I could not see that it was bad at first, but now it is working fine after removing the fuse and cleaning the connection then resoldering. card boots and works fine.

My question is how safe it is to run this card without a phase? when I solder on a new vrm MOSFET the card works fine but will crash if I play a game after a minute or two. if I remove the MOSFET no crashes, but I lowered the power limit to 80%. with the MOSFET installed it will mine without issue and no lockups but cannot game