XFX RX 590 8Gb Fat Boy

Seller Note “Was used for gaming then stopped working. Not detected.”


  • Resistances mostly look fine
    • Vcore – 1Ω
    • Vmem – 341Ω ! (high, should investigate, will compare vram if possible Micron D9VVR -> MT51J256M32HF-80:B)
    • VDDCI – 32.4Ω
    • Display Rail – 22Ω
    • 1.8v – 2.2KΩ
    • 5v – 6KΩ
    • 12v – 2.7KΩ
    • 3.3v – 1.5KΩ
  • Voltages missing. Apart from 12v, 3.3v and 0.91v. I was hoping this would be the case, as sometimes not detected with all the voltages can end up being a faulty core.
  • Quite excited to analyse this one. I have a regular XFX RX580 8Gb with a vram issue, but I would expect them to have similar PCB layout (will need to check).
  • Hopefully fixed now! 🙂

Investigating Missing 5v Rail

BM1117-ADJ Is an adjustable voltage regulator https://datasheetspdf.com/pdf/617638/BooklyMicroelectronic/BM1117/1

XFX RX590 5v Voltage Regulator
PinRX 580 (working)RX 590 (this)
1 (adjust)470Ω / ~3v470Ω / 2.45v
2 (Vout)556Ω / 5v556Ω / 3.23v
3 (Vin)K++Ω / 12v6KΩ / 12v

I think we would have to suspect the voltage regulator. The resistors in the voltage divider are a possibility, but the relative voltage drop on the adjust pin looks in proportion between the working 580 and the 590. Another possibility is a partial short on the 5v output, but the resistance is exactly the same on the Vout pin for the working card, so this is again unlikely. Unfortunately, I don’t have immediate access to any adjustable 5v voltage regulators, they generally have just a ground pin rather than the adjust pin. I can order some, rather than remove the resistive divider.

The BM1117-ADJ is somewhat harder to come by than other similar voltage regulators, so I am looking to try the more popular AMS1117-ADJ instead https://components101.com/regulators/ams1117-1a-ldo-regulator-pinout-datasheet

RX 590 Fat Boy – Fitted new 5v regulator

Fitted a new AMS1117-ADJ and delight! It now generates 5v! Hopefully, it was just the 5v regulator that became faulty and no other reasons. If so, hopefully, a nice straightforward fix! 🙂

Stress Testing

  • Kombuster HD – passed.
  • Furmark HD – passed.
  • 3D Time Spy – passed.