SOLD AS-IS FOR PARTS OR REPAIR. CARD IS NOT FUNCTIONAL AND DOES NOT OUTPUT VIDEO.
I purchased this card already damaged/non-working as a repair project. According to the previous owner, the complete PC was shipped with the graphics card installed and the card was damaged during shipping.
I've spent several hours troubleshooting it and am including my findings below for anyone interested in repairing it.
Original damage / work performed:
Two small PCIe AC-coupling capacitors near the edge connector had been physically knocked off the board. Both were replaced. One capacitor had a damaged/lifted pad, which was repaired and continuity was verified.
No GPU reflow or reball has been attempted. The GPU package has NOT been heated with a hot-air station.
Current symptoms:
With normal PCIe auxiliary power connected, the card will power up and the fans perform a normal-looking startup sequence (initial fast spin followed by slower operation), but the card does not output video and generally causes the motherboard to hang during POST around code 97.
When installed as a secondary GPU alongside a known-good Radeon Pro W5500, the system can progress farther through POST and briefly initialize the working GPU before hanging.
The failure has shown some state-dependent/intermittent behavior: during testing the system was occasionally able to POST with the 7800 XT installed and powered, but the 7800 XT still did not enumerate in Linux/lspci. The original POST-hanging behavior subsequently returned.
With the 7800 XT's auxiliary PCIe power disconnected, the computer POSTs and boots normally, but the 7800 XT does not enumerate.
Diagnostics performed:
Tested both onboard VBIOS switch positions — same behavior.
Tested card through an x1 PCIe extension/riser — same general failure.
PCIe PERST# verified to assert/release.
PCIe reference clock activity verified at the card.
Both VBIOS flash ICs have approximately 1.8 V supply.
Oscilloscope confirms the GPU actively reads the selected VBIOS flash during startup (/CS, clock and data activity observed).
12 V input is present at the main VRM power stages.
Several auxiliary/memory-related voltage rails come up normally.
GDDR6 memory packages warm during startup, and their associated power circuitry is active.
GPU/GCD itself warms during attempted initialization.
Main GPU Vcore multiphase VRM does not begin switching. Vcore remains essentially at 0 V.
Oscilloscope testing of the Vcore switch nodes showed no PWM/startup attempt.
Vcore does not appear to be hard-shorted. With the card otherwise unpowered, a brief external test at approximately 0.9 V drew approximately 3.2 A (~2.9 W), with the central GPU die warming slightly and no abnormal localized hotspot observed with a thermal camera.
No obvious shorted/hot component was found elsewhere on the board using a thermal camera.
PCIe bus rescans under Linux did not cause the card to enumerate.
Based on these measurements, the card is clearly performing at least part of its early startup sequence, but it does not successfully reach normal PCIe/GPU initialization and the main GPU Vcore rail is never enabled.
I do not know the root cause. Possible BGA, GPU, memory/interconnect, power-sequencing, firmware/control, or other board-level faults have NOT been ruled out. I am selling it because further diagnosis/repair is beyond the equipment I have available.
This would be best suited to someone experienced with GPU board-level repair who has appropriate diagnostic equipment and/or BGA rework capability.
Please examine photos carefully, particularly the previously repaired PCIe capacitor area. I am happy to provide additional measurements or information about the troubleshooting already performed.
Again: this is a NON-WORKING graphics card sold strictly AS-IS FOR PARTS OR REPAIR. No guarantee is made that the GPU core, memory, PCB, or any other component is repairable.
