RX6900XT - U7102 (HT32F52342) potentially dead - how f^cked am I?
TL;DR the MCU that controls fans and checks PEX voltages indicates proper PEX connection via LEDs is most likely dead. How hard will it be to find the code to program a replacement?
Long version:
Hi there! A couple of months ago I bought an Aorus RX6900XT Waterforce (it's the watercooled variant of Gigabyte RX6900XT OC 16GB, and has the same board and most components) as a "state unknown" for pretty cheap. I've repaired GPUs in the past, I am an electronics enthusiast since I was 7, so I know some stuff about repairing GPUs.
The card (of course) was dead on arrival, which I fully expected (I had hoped that it might be alive, and be "untested" because someone who got it in some way didn't have a water loop and didn't want to test it dry, but tough luck).
3.3V from PCI-E showed a short, so I soldered a wire onto a cap that (according to board view for this card) was connected to this line, put some power through it, and i tested it up to 2A (max of what my bench PSU is capable of), and it took the entire 2A, with the voltage as low as 2.6V, so I guess that's a little high according to the specification that says 3A is the absolute maximum. Then I whipped out a thermal camera (admittedly a pretty shitty one, because it's an old Caterpillar S60 smartphone with the FLIR thermal camera), and I've noted that U7102 (HT32F52342 [Click for datasheet]) is getting pretty hot (55-60 deg. C with the 2A being pulled from my PSU). Then, poking around further, I've noticed that U7104 (MP1475 [Click for datasheet]) was kerpow'd. This chip was supposed to take +12V_BUS_B to generate the 5V_LED line, which through R7135 (470Ohm) supplied ADC_VREF for U7102 (the microcontroller). So it's pretty safe to assume, that when U7104 went ^(nuclear), it took U7102 with it to Valhalla, sadly.
And here's my problem... Knowing, that it's a microcontroller, and seeing no external Flash memory anywhere near it, I fear the worst, that the program was on the "...128 KB of embedded Flash memory for code/data storage", to quote the manufacturer of the MCU.
If the U7102 is indeed ker-chowed to all hell (and the thermal camera/current draw would suggest so), how hard would it be to obtain the code that was used to program it? Is it something that's available somewhere in the Internet? My last repaired GPU was back in the GTX2XX era, so I am a bit rusty in that regard, I don't even know how to start looking for it
If You'd need the boardview, DM me. I'm unsure if I can post the file here, so I will just send it to anyone interested via DMs.