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Centris 650 PSU Failure
Posted by: betaporter on 2024-12-23 18:45:30
My beloved Centris 650's PSU made a god-awful noise and died this evening while booting it up for the first time in a while. The PSU appears to have failed. Closer inspection reveals that, inside the PSU the IC at IC2 has blown.

Anyone have any idea what this part might be? I did some Googling but couldn't track down a diagram for this PSU. That said it does seem to be a pretty straightforward design, so I suspect I can work out the failure, but would love to learn if someone here is already familiar with this particular failure mode.

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Posted by: jmacz on 2024-12-23 22:27:41
Here’s a pic of a Quadra 650 PSU which might be the same.

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AS3843 switching power supply control?

You should probably figure out why it burned out first though.
Posted by: betaporter on 2024-12-24 06:28:50
Thanks! That would make sense, based on where on the board this chip is.

You should probably figure out why it burned out first though.

100% on this. The way this part failed, I'm guessing high voltage got to it. After I posted last night, the fuse also appears to have blown. I'm wondering if one of the transformers failed, but I'm not sure yet. I'm going to be tearing this thing down after the holidays to get to the bottom of it.
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