GTX 1080 FE repair, now i am stuck.....

[Tadango]

I bought a defective GTX 1080 FE to see if i can figure out what is wrong with it (for fun, it was cheap). Symptoms when i received the card: No output in post / detection by Windows, fan always at 100%. Not heat from the card.

I don't know the history of the card but there is a dent in the back cover. That back cover has a protective plastic film in which 2 capacitors from the 2x PCIe lane were stuck / jammed, and ripped of the PCB. Other then that the card looks perfect.

So first things to check were power and resistance, but all looked good (VCore, VMem, PEX and PLL). Voltages were spot on and the resistance is the same or slightly higher then what is reported online, so no worries about a shorted component. With the heatsink removed the GPU does get slightly warm with my finger on it, but not hot at all, so it isn't doing much.

I checked the bios chip and i can read / write it without any errors. It also contained the original bios in the first part but garbage in the second part. I cleared the chip and flashed the correct bios to make sure, but that didn't change anything.

Next i hooked up my scope (Rigol 1054Z) to the CS, CLK, Data in and Data out of the eeprom chip but that doesn't show anything. Only CS is high, the rest is low. Since CS is active low it means the chip isn't even selected.

So this looks like the GPU is not starting at all, like it is stuck in a reset state. It get's power so i wonder what could be keeping it in the stuck state? I tried to trace the B11 line from the PCIe slot (Power Good signal) but it disappears in a via and i cannot find it again.

So..... what else can i check? GPU die is perfect optical, no cracks or chips. Cooler was not removed before (screws were sealed). Maybe the card was dropped and caused the GPU to make bad contact? Is the next step a reflow? I got a reflow gun so that is one thing i can try.....