VOGONS


First post, by Cypher321

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Picked up a GF4 4200 ti awhile back for a good price as it was being sold for parts/not working. The card does display but it has some green artifacts that I believe are typical of a memory issue:

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A visual examination showed one (maybe two?) of the legs on one of the memory chips having broken off from the chip:

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Any thoughts on how to repair this? I read a few random threads on various forums suggesting shaving away the plastic of the chip to the metal and resoldering - seems a bit aggressive to me but I also don't see much to work with given how the leg failed. FWIW, I do have access to an EE lab at work plus my own (lower grade) equipment at home.

Reply 1 of 8, by kingcake

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If you have access to a lab it would easy to replace that chip with a PCB preheater and hot air. Or even low melt solder. Before you jump to action pull the datasheet on that chip and see what that pin does.

Reply 2 of 8, by BitWrangler

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Don't think of it as randomly gouging at precision equipment, think of it as 1:72nd scale dinosaur femur excavation. Seriously if you mask off anywhere where tools might slip, you can't really do more damage than it's got, can still replace chip if you mess up.

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 3 of 8, by kingcake

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BitWrangler wrote on 2024-03-14, 04:21:

Don't think of it as randomly gouging at precision equipment, think of it as 1:72nd scale dinosaur femur excavation. Seriously if you mask off anywhere where tools might slip, you can't really do more damage than it's got, can still replace chip if you mess up.

Those mini cordless engraver pins everyone is using to grind traces would probably work well here. But I don't know if it's worth buying something if he has access to an SMD lab.

Reply 4 of 8, by waterbeesje

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I'd Dremel the plasticaway very carefully and solder in a small wire. It does requirea steady hand and small tip but it is definitely doable with a regular iron.

Stuck at 10MHz...

Reply 5 of 8, by Unknown_K

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First off get the rest of that pin off the pin next to it and see if those 2 are shorting out something important.

Collector of old computers, hardware, and software

Reply 7 of 8, by snufkin

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Looking at the datasheet for the K4D261638E (think that's the right part?) then the broken leg is 54 - DQ8. Leg to the left (53) is N/C and leg to the right (55) is Vddq. So I think there's a good chance the chip will be ok, even if the PCB pad for leg 54 has been shorted to leg 53. Datasheet just says the NC is recommended, not required. Possible crack on leg 55 probably doesn't matter, but a dab of solder might stop it failing later.

Reply 8 of 8, by Cypher321

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Thanks for all the feedback folks. I'll bring home my microscope from work and take a look at the card again this weekend. Assuming mechanical manipulation doesn't work, I'm feeling good that the 'shave and solder' technique is the way to do.

snufkin wrote on 2024-03-14, 10:54:

Looking at the datasheet for the K4D261638E (think that's the right part?) then the broken leg is 54 - DQ8. Leg to the left (53) is N/C and leg to the right (55) is Vddq. So I think there's a good chance the chip will be ok, even if the PCB pad for leg 54 has been shorted to leg 53. Datasheet just says the NC is recommended, not required. Possible crack on leg 55 probably doesn't matter, but a dab of solder might stop it failing later.

Correct on that p/n and thanks for the tip!

kingcake wrote on 2024-03-14, 04:24:
BitWrangler wrote on 2024-03-14, 04:21:

Don't think of it as randomly gouging at precision equipment, think of it as 1:72nd scale dinosaur femur excavation. Seriously if you mask off anywhere where tools might slip, you can't really do more damage than it's got, can still replace chip if you mess up.

Those mini cordless engraver pins everyone is using to grind traces would probably work well here. But I don't know if it's worth buying something if he has access to an SMD lab.

Honestly couldn't tell you what the EEs keep in their lab (I'm a ME by training and profession) but I'll keep an eye out assuming I need to do some shaving.

I'll post an update after I've had a chance at repairing the card. Really hoping to get this card working for my all purpose Win98SE system.