I have an AT power supply (custom for a specific computer model) and it does not power on. I have had some experience repairing power supplies so normally it's not a big deal. First thing I noticed is the fuse is not blown, however it does not output any power. I have checked for shorts on the secondary side, checked all the transistors, including the main switching transistor, all the diodes, the optocoupler and photothyristor seem to work. I get voltage, about 300vdc, if I remember, at the primary side bridge rectifier. I have even checked all the resistors and they are at the rated value. From what I can tell, the main transistor must not be switching at all. Though if I keep a meter on the output, and power it on for a few seconds then turn it off, after about 15 seconds or so it jumps from 0v dc to 0.2v dc, which makes me think that there may be a collapsing field in the transformer that may be generating some current, though I don't know for sure. I did a full recap on it since some minor leakage was showing, even though the leaking capacitors didn't show any ESR issues yet.
Any help will be appreciated, as I have been banging my head on this issue for most of this week.
Thanks
Any help will be appreciated, as I have been banging my head on this issue for most of this week.
Thanks
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