GPU broken part - unsure what is it is and how to fix. - Page 1
Forum section: electronics / repair

author: sparkbot91
author_rank: Newbie
timestamp: June 27, 2023, 03:36:05 am
content: I broke what I believe to be a capacitor or a transistor on a gpu board which I intend to sell. I need to fix it and i am unsure of the best way to go about it without risking further damage to the board.

author: Shonky
author_rank: Frequent Contributor
timestamp: June 27, 2023, 05:28:58 am
content: It's likely identical to the part next to it - a surface mount electrolytic. How can it be a transistor?Clean pads, buy a new part, and solder it on? It would be a simple job for any one half competent with soldering.

author: Swake
author_rank: Frequent Contributor
timestamp: June 27, 2023, 06:19:41 am
content: Exercise your solder skills first on boards that have no value to you. Some very good youtube tutorials out there. Watching only a couple is not going to make it. You'll need the right tools too.Alternatively forward the GPU to someone with experience.

author: MathWizard
author_rank: Super Contributor
timestamp: June 27, 2023, 08:42:54 am
content: I'm afraid to use hotair on SMD can style caps. The value will no doubt be the same as all thee others near it, it's just an output or input rail filter/storage cap.It would probably run without it too, but the more the better. And the size won't matter too much, as long as it's no big amount smaller that rest of them. You could probably salvage something similar off a mobo, or cablebox, or even a printer. Just make sure it's rated high enough voltage. Those are probably low ESR caps tho, on the GPU.If you have the time, use a DMM and find what voltage rail it's attached too. Some rails only have 1-2-a few caps, so yeah, you can't always get away with assuming it won't matter.With flux and copper braid, I'd clean the old solder off the PCB, and then tin/clean the replacement, and then tin the PCB and you should have enough metal showing on either end, to tack it down/reflow it.

author: ArdWar
author_rank: Frequent Contributor
timestamp: June 27, 2023, 09:02:24 am
content: Quote from: MathWizard on June 27, 2023, 08:42:54 amIt's still quite hard to do using hot air even if you disregard all the electrolyte/polymer precautions. Them usually mounted to ground and supply pours doesn't help at all, not to mention the plastic base.It's easier to pre-wet the leads and pads, put them together, and heat from the side using iron. Hope your iron got enough capacity to re-melt them together. This way you also saving the other caps next to it from getting roasted.Also for this specific case: Make sure you don't bridge the pads to one directly next to it

author: wraper
author_rank: Unknown
timestamp: June 27, 2023, 09:11:51 am
content: Buy 820uF 2.5V aluminumpolymerSMT capacitor and just solder it instead of missing part. If you still have a missing part and it still has terminals, you can solder it back. You likely need to preheat the board somehow, otherwise soldering iron likely won't have enough power to solder on PCB with heavy copper planes. For example you could put in an oven heated to 120oC, after 10 minutes take it out and solder quickly before it cools down. You do not need to clean the pads as new capacitor terminals should fit into caves left from the old cap. Some gel or liquid flux will help to do the job easier.