Seller Note “VRAM issue” (not detected would be more accurate)
Summary
- Superficially looks like a cheap XFX RX 580, without a backplate
- Decent condition, with the original box, bought for £20.98 (curiosity buy!)
- Resistances
- VCore – 1.9Ω
- VMem – 93.5Ω
- VDDCI – 38.7Ω
- Display Rail – 42Ω
- 5V – 824Ω
- 1.8V – 2.3KΩ
- 3.3V – 2.3KΩ
- 12V – 4.5KΩ+ (slot), 2.3KΩ+ (8 pin)
- Power on testing
- Not detected
- Has 5V, but missing 1.8V and all derived voltages e.g. Display Rail, VDCCI, VMem, VCore
Investigating missing 1.8V rail
Taking a look at the 1.8V LDO we have a uP8801S https://pdf1.alldatasheet.com/datasheet-pdf/view/1116505/UPI/UP8801S.html
VIN (pin 3) is present at 3.3V, but EN (pin 2) is very low at 0.044V
Need to investigate the circuit driving the enable volatge