Hi folks. Long-time lurker, finally a tricky enough problem that I thought I'd ask some advice.
This PSU seems well known. I picked it up 2nd hand about a year ago to replace another that had died. It was working fine for a while then stopped. Short story is that it was being run off a 240v generator which developed a problem leading to possible overvoltage. However, it passed a physical inspection - nothing burned, popped or unusual there (photos to follow).
I've taken measurements on the primary side up to the transformer and it appears to be working fine there but it won't power up. I'm measuring +5v on the standby pin of the ATX connector (pin 9) but, oddly, I'm also getting +2.5v on pin 21, which is supposed to be +5v when powered on.
When I try to power it on (jumping pins 15 and 16) nothing happens. Some kind of protection must be kicking in though, because +5vsb reads 0, although pin 21 still reads +2.5v. Actually I've just noticed that pins 9 and 21 are adjacent to each other, so maybe I should start with following traces and looking for a short? Nothing is visibly wrong so far.
Thanks in advance.
This PSU seems well known. I picked it up 2nd hand about a year ago to replace another that had died. It was working fine for a while then stopped. Short story is that it was being run off a 240v generator which developed a problem leading to possible overvoltage. However, it passed a physical inspection - nothing burned, popped or unusual there (photos to follow).
I've taken measurements on the primary side up to the transformer and it appears to be working fine there but it won't power up. I'm measuring +5v on the standby pin of the ATX connector (pin 9) but, oddly, I'm also getting +2.5v on pin 21, which is supposed to be +5v when powered on.
When I try to power it on (jumping pins 15 and 16) nothing happens. Some kind of protection must be kicking in though, because +5vsb reads 0, although pin 21 still reads +2.5v. Actually I've just noticed that pins 9 and 21 are adjacent to each other, so maybe I should start with following traces and looking for a short? Nothing is visibly wrong so far.
Thanks in advance.
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