Seller Note “Short. Can see 3.3v PCI pin damaged”
Summary
- Does indeed have a short on 12v PCI slot.
- Vcore showing as 5.6Ω, as is 12v PCI. Vmem 26Ω.
- Was quite dirty, no visible damamge. Very cheap, was going to be thrown away by seller.
- Even if full functionality is restored, I would think this card will be hard to sell and be more of a repair trophy if I can succeed! 🙂
Dealing with the short
Suspect one of the VRM phases is faulty. Measuring ESR.
| Phase | ESR Ω |
|---|---|
| 1 () | 1.08 |
| 2 () | 1.08 |
| 3 () | 0.89 |
| 4 () | 1.08 |
The high-side MOSFET shown top right is likely the source of the short. There is also so corrosion showing in the bottom right-hand corner, this could be a bad sign.
Trying to remove the MOSFET proved very difficult, I had to back off for fear of causing further damage. I tried heating for perhaps up to a minute with 450 degree C heat and higher airflow. The board was getting very hot and a nearby MOSFET started to dislodge, whilst the problem one could only be wriggled. I have seen this before EVGA GTX 980 Ti 6GB 06G-P4-4995-KR. It can be because the MOSFET has fused itself to the pad (that corrosion could be a factor). It is likely a mistake to try to push ahead with heat, so I will need to add this to the ‘to be carefully dremelled’ list 🙂
It is this MOSFET https://pdf1.alldatasheet.com/datasheet-pdf/view/1119196/UPI/M3054M.html
MOSFET Replacement
Need to write up notes:
The MOSFET couldn’t be removed with even 450 degree C heat, it was fused to it’s pads. The heat was so high that the adjacent high-side MOSFET was also desoldered!
Used a Dremmel to remove the faulty MOSFET (add pictures). I think it’s fair to say this and my other attempt (EVGA GTX 980 Ti 6GB 06G-P4-4995-KR) indicate I have a lot to learn! The good news is that the short has resolved, the bad news is I have badly damaged the VS pad especially (there are some small scratched areas which expose the sublayer, which seems to be ground). Still, this is very much a learning card for me.
Pads damaged
The short is now resolved
Risky Voltage test with 2/4 phases is encouraging, a picture was shown (only chanced the BIOS screen)! This is enough
Repairing the damaged pad
Dealing with the damaged pin
Here you can see the damage to the 3.3v PCI finger, plus minor damage to other pins, not sure how they did this! The 3.3v finger can be folded right back and I cannot risk any kind of testing with it like this, as it is highly likely to either break off and/or short the PCI slot.
As the board was very cheap and most of the finger is there, I will opt for a superglue ‘quick fix’. I will refine this if I can resolve the short and everything else is healthy. Seems solid enough for now, will scrape of the excess glue later.
