How reliable are replaced motherboard MOSFETs over the long term? - Page 1
Forum section: electronics / repair

author: ksio89
author_rank: Contributor
timestamp: April 06, 2022, 05:40:09 pm
content: To make a long story short,in this threadI reported an issue with my PC motherboard (Gigabyte Aorus B450 M), where you could hear a buzz and static sound coming from rear phone connector, likely caused by improper grounding. I turned the PC on outside the case, believing that keeping it away from I/O shield might help, but then I smelled and saw magic smoke coming from it. Turned it on again with another PSU, same smell and sighting of smoke. Stubborn as I am, I turned it on once again with my PSU, and this time the MOSFETs from the VRM circuit near CPU socket (AMD AM4) blew up and caught fire, I ain't joking. Finding that the mobo was still on warranty, I sent it back to the shop where I bought it and requested a new motherboard. However the shop denied the replacement, just replying to me that they were going to send it to the manufacturer for repair. I objected to the repair and contacted consumers rights enforcement body in my country, but despite this, they contacted me today and said the repair is done and that they are sending it back, talk about an audacious shop.The issue now is that I am very wary of the reliability of this repair in the long run, as I have the impression that I got a time bomb in my hands and that the replaced (or other) components are likely to fail again not longer after the warranty ends (22/06 or 06/22). I haven't received and tested the repaired mobo yet, but do you guys think that I should accept the repair if it's in working condition again, or that I shall argue with the shop for a full procut replacement? Actually, I'm not even sure if there aren't other faulty components as well and that MOSFETs are just victims of them. Here's a photo I took after the MOSFETs blew up, the part code is 4C06N YEMY18:

author: TheMG
author_rank: Frequent Contributor
timestamp: April 06, 2022, 06:14:07 pm
content: I can't speak for the laws in your particular country, but usually the place of purchase (retailer/shop) has no obligation to replace a defective product that is covered under the manufacturer's warranty. Of course, it all depends if they have any kind of agreements with the manufacturer of the products they sell as far as how warranty issues are handled. Quite often past a certain time frame it's usually up to the purchaser to deal with the manufacturer directly for warranty service.Read the terms of the warranty for your product. Usually it will say that the manufacturer will decide whether to repair, replace, or refund the product. It's up to them and what they deem to be appropriate based on the failure.As for how long the repair will last...?? Could be 5 seconds, or could be 100 years. No way to know. Far too many factors at play. Just because one component failed, does not necessarily mean the rest of them are also on the brink of failing. Defective components do happen from time to time, that's why warranties exist.

author: ksio89
author_rank: Contributor
timestamp: April 06, 2022, 07:10:50 pm
content: It's more or less a standard practice that for PC hardware parts, the warranty duties in the first year are usually handled by the place of purchase, and from the second and on, directly by the manufacturer. But you're right, I'll have a look at Gigabyte website to find out what's their policy about RMA and contact their local sales representant. Unfortunately, the warranty information card was sent along with the mobo.edit: it seems repair is an acceptable procedure by Gigabyte, according to theirwarranty terms. The information is pretty much the same in my language, so I guess I have to bite the bullet and hope it will work and won't blow up again in the short term.

author: TheMG
author_rank: Frequent Contributor
timestamp: April 06, 2022, 09:01:03 pm
content: Quote from: ksio89 on April 06, 2022, 07:10:50 pmEven in that case, the place of purchase is just acting as a middleman, taking care of the process and any required shipping for you. They will usually contact the manufacturer, which will advise them to either have the product shipped to a repair center for repair (or further testing), or the manufacturer will tell the place of purchase to give you a new one. But almost always, it's the manufacturer that makes the decision.In this case, they've obviously decided repair was the most appropriate and cost effective option.

author: wraper
author_rank: Unknown
timestamp: April 06, 2022, 09:09:59 pm
content: Quote from: TheMG on April 06, 2022, 06:14:07 pmExactly opposite in Europe. Manufacturer is not obliged to do anything, retailer has no legal right to refuse dealing with warranty claims.QuoteDunno about Brazil but in EU you have a right to request a new replacement only in first 6 months or after an unreasonable number of repairs already done.QuoteI don't see anything extraordinary that would prevent a quality repair to be made.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: April 07, 2022, 09:14:35 am
content: IMHO simple what kind of warranty of the purchase agreement it is, personally not having to do with law, but it's so common known that there're many kinds of warranty in our market society

author: Rasz
author_rank: Super Contributor
timestamp: April 08, 2022, 08:43:14 am
content: as long as both transistors were replaced along with a driver it will be fine

author: ksio89
author_rank: Contributor
timestamp: April 08, 2022, 05:52:22 pm
content: Quote from: Rasz on April 08, 2022, 08:43:14 amWhere is it in the picture? I wanna do a visual inspection before even attempting to turn it on.

author: james_s
author_rank: Super Contributor
timestamp: April 08, 2022, 06:07:58 pm
content: I have repaired lots of things that went on to function perfectly for much longer than they lasted prior to the initial failure. If done properly a repaired item should be just as reliable as a new one.

author: Rasz
author_rank: Super Contributor
timestamp: April 09, 2022, 10:31:56 am
content: https://www.pcgamesn.com/gigabyte-aorus-b450-8-3-phase-vrmDG01 DG02 and DGU1https://www.renesas.com/us/en/document/dst/isl6625a-datasheetat the very leasthttps://www.personal-view.com/talks/discussion/21417/motherboard-vrm-power-guide