PowerColor Red Devil RX 580 OC

Summary

  • It’s this card https://www.techpowerup.com/gpu-specs/powercolor-red-devil-rx-580-oc.b4432, apart from scratches to the rather nice steel cooler (sustained due to poor packaging), it seems in decent condition and has the warranty sticker intact.
  • Resistances
    • VCore – 0.6Ω
    • VMem – 29.4Ω
    • VDDCI – 20.1Ω
    • Display Rail – 22.6Ω
    • 5V – 3.22KΩ
    • 1.8V – 3.8KΩ
    • 3.3V – 218.3Ω (seems a little low)
    • 12V – 3.87KΩ (slot) ~4KΩ (ext)
  • So, there seems to be something intermittent about the voltages. A couple of times, I noticed all voltages including (1V on the display rail) and the core getting hot. Other times, only 5V, 1.8V and a low Display rail ~0.93V (low) and no VCore, VMem and VDDCI.
  • Given the low display rail voltage, I suspect an issue perhaps with the feedback circuit or the GS9238 itself.

Investigating the Display Rail circuit

I would like to check the feedback resistors. There is a voltage divider.

TODO Add a better diagram

Net Short (0.8V) -> R903 (1KΩ) -> PR903 (0Ω) -> FB <- R950 (17.4KΩ) <- GND