AX1200i Repair / Common Failures?

FrankD400

Limp Gawd
Joined
Jan 31, 2013
Messages
154
Does anyone have any pointers where to start looking for failures in these PSUs? I got a refurb, it died just barely within warranty after purchasing from Micro Center but COVID hit and now it's just sitting there like a lump. I bought another one from MC, it was dead out of the box.

I don't have any familiarity with SMPS, but I've got a scope, a decent DMM and I'm not afraid to zap myself! Kidding aside..

The PSUs both have the same behavior; sometimes they will start (other times they will self-detect a fault and light up the no good LED) and run anywhere from a minute to a few hours. The runtime has no correlation to load, I can stress both my GPUs and the CPU (~1000w) and it will run for an hour.. sometimes it will only make it to POST.

If there's some common failures I could poke at, advice would be greatly appreciated.
 
Don't buy refurbs - they have already been stressed by a burnup of something already once. Anyways, unplug and discharge the caps. Start with checking the solder joints because whatever failed before will have new solder on it. Look for visual defects. All in all -it's probably not worth your time unless you want to become an expert in electronics repair, which doesn't pay that well in a throw away society anyways. Power supplies are relatively cheap. Go with a brand name and they will last a long time.
 
Mega, unfortunately it was all I could afford when I went to buy one. Usually I buy SeaSonic platinum units. I'm looking for repair info not PSU buying advice. AX1200is have a high failure rate according to some googling.

Having a few oscilloscopes I think I'm comfortable getting into (attempting) a repair.. ;) thanks, though.
 
The easy stuff to check are capacitors and solder connections, so that's where I would start. Beyond that, I wouldn't know how to check the other components.
 
The PSU running for a variable amount of time and then cutting out sounds like bad solder joints. It wouldn't surprise me because lead-free solder is trash that gets very brittle when continually heat cycled and is subject to cracking and failing.

It'd be good to look for other obvious signs of failure, like burned PCB where components got too hot.
 
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