VOGONS


First post, by Kahenraz

User metadata
Rank Oldbie
Rank
Oldbie

I bought this GeForce FX 5900 on eBay for a good price a few months ago and I'm just now getting around to looking at it. The listing stated:

Powers up and fan spins when plugged in to motherboard but no display. Strictly for parts. Sold AS IS.

This is not strictly accurate. When I tested it, the entire system powers on briefly with the GPU fan spinning momentarily before everything shuts off on its own. This isn't very helpful and the cause for the problem could be almost anywhere.

Here are some photos of the board:

IMG_20211125_213501_resize_34.jpg
Filename
IMG_20211125_213501_resize_34.jpg
File size
91.42 KiB
Views
237 views
File license
Public domain
IMG_20211125_213712_resize_45.jpg
Filename
IMG_20211125_213712_resize_45.jpg
File size
93.22 KiB
Views
237 views
File license
Public domain

The board uses Hynix HY5DU283222AF-22 GDDR memory.

IMG_20211124_223524_resize_82.jpg
Filename
IMG_20211124_223524_resize_82.jpg
File size
40.05 KiB
Views
237 views
File license
Public domain

I wasn't able to find anything obvious from a visual inspection so I proceeded to remove the heatsink and fan. What I found underneath was a surprise.

IMG_20211125_213527_resize_69.jpg
Filename
IMG_20211125_213527_resize_69.jpg
File size
389.09 KiB
Views
237 views
File license
CC-BY-4.0

The previous owner had sanded down the die to the copper surface. The underside of the painted heatsink had also been sanded to the bare aluminum. I don't know how much of an improvement this would have made over simply replacing the stock cooler with an aftermarket one.

There was also some damage to the surface of the clock crystal as a result of the sanding but I don't know if this caused any damage to it.

A closer inspection under a microscope revealed a significant oxidation and a small amount of corrosion but nothing alarming at first. I had initially intended to wash the board and then try reflowing some of the joints but then I spotted this.

IMG_20211125_213551_resize_59.jpg
Filename
IMG_20211125_213551_resize_59.jpg
File size
303.48 KiB
Views
237 views
File license
CC-BY-4.0

I can only attach 5 images per post. Read on below...

Last edited by Kahenraz on 2021-11-26, 04:14. Edited 1 time in total.

Reply 1 of 6, by Kahenraz

User metadata
Rank Oldbie
Rank
Oldbie

I use these small red stickers to mark any problems as I work so that I can find them again quickly in the future. This is especially helpful in the event that I need to set it aside while waiting for a replacement part.

Here is a closer picture taken with my microscope. At some point during maintenance or resurfacing, one of the capacitors got knocked off. This is beneath the large black heatsink on the back of the card where it should have been protected from this kind of damage.

IMG_20211125_213615_resize_97.jpg
Filename
IMG_20211125_213615_resize_97.jpg
File size
126.13 KiB
Views
225 views
File license
CC-BY-4.0

I am continuing my triage but this repair has just been upgraded from "mystery" to "promising"!

Here is a photo of the damaged clock crystal. It's probably fine.

IMG_20211125_221807_resize_53.jpg
Filename
IMG_20211125_221807_resize_53.jpg
File size
162.83 KiB
Views
224 views
File license
CC-BY-4.0

I'm also finding fine copper shavings as a result of the sanding process. It looks like there were other SMD components that ended up with some kind of surface damage as well. It's possible that there is a short somewhere besides the missing capacitor.

IMG_20211125_222237_resize_56.jpg
Filename
IMG_20211125_222237_resize_56.jpg
File size
340.57 KiB
Views
223 views
File license
CC-BY-4.0

Upon further inspection it's actually even worse than I thought. This is pretty terrible. C97 reads as a 0 ohm dead short.

IMG_20211125_224105_resize_85.jpg
Filename
IMG_20211125_224105_resize_85.jpg
File size
240.33 KiB
Views
218 views
File license
CC-BY-4.0
IMG_20211125_224010_resize_29.jpg
Filename
IMG_20211125_224010_resize_29.jpg
File size
234.81 KiB
Views
218 views
File license
CC-BY-4.0
Last edited by Kahenraz on 2021-11-26, 03:47. Edited 1 time in total.

Reply 4 of 6, by BitWrangler

User metadata
Rank l33t
Rank
l33t

Any surface mount that got ground is probably going to be out of spec even if it still resists or capacitates... In extreme modding you can "trim" values like that, carefully, but random mowing at them will have the values much less than they should be.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 5 of 6, by Kahenraz

User metadata
Rank Oldbie
Rank
Oldbie

I'd like to make an attempt at fixing this but I'll need another card to use as a reference for the damaged components. This is probably a lost cause but these SMD parts are so easy to replace that I think it's worth a try.

The thing I am worried about most of all is whether or not some of the debris got under the GPU or memory chips and is causing a short there.