Graphics card uses too much power and fan doesn't spin.

I bought this card on ebay. Seller has no return policy. I knew the risks, so I'm not crying foul. I wanted a low profile, single-slot card that's well supported under Linux, for use in server. This fit the bill, perfectly.

I asked two GPU repair services and was declined by both, as they consider the card too old and cheap. I still think the problem might be something fairly basic that perhaps even I could fix. Seems worth a shot, as I have nothing to lose at this point.

Model: PowerColor RX 550 4 GB Low Profile

This exact one: https://www.powercolor.com/product-detai...

Symptoms:

• Card seems to work properly, producing clean signal on both outputs.
• Meanwhile, fan is not spinning.  Even when running 3D benchmark, fan does not spin.  Pushed fan with finger, still doesn't start, although I felt no mechanical resistance.
• Benchmarks run much too slowly, compared to other cards of the same model, even when cooled by another fan and temps are in the reasonable range. The GPU seems to know its power budget is nearly exhausted, hence shader clocks never ramp up.
• Software reporting claims high idle power: 32 Watts with both display outputs connected @ 60 Hz.  The max power for this card is only 50 W.
• After disconnecting fan, idle power drops to 25 Watts.  Still way too high.  Disconnecting second output drops idle power to 16 - 18 W.  Other RX 550 have an idle power of 4 W, and that's with the fan running!

No visible signs of damage, scorch marks, melted components, or missing chips.  Card appears pristine. No dust, even after removing shroud.

How the card is reporting power usage makes me wonder if it might be some defective or failed component in the card's VRM. The base power started way too high and each time I reduced the electrical load (i.e. disconnecting fan, disconnecting second monitor output), the reported power usage dropped by an amount that was similarly too large.

Is there any reference I could follow to narrow down any failed discrete component? I have a 15-year-old CPU/motherboard and out-of-service PSU I can use on the test bench, which I don't mind losing, if I accidentally short something while trouble-shooting. As for repair equipment, I pretty much only have a multimeter and soldering iron. Took an intro to electronics class at a community college, many years ago.