How To Repair Atx Power Supply No Power. As usual one has to remove the 4 screws in order to remove the top casing. All the filter caps in primary and secondary side looked good except the main fuse.
Require you to hold the power button in for a few seconds before the power supply shuts down again. If the PG signal timing is between 100ms and 500ms the PSU should be fine otherwise the PSU have some problems. -make sure all secondary diodes are working.
The first thing I do was to look at the circuit board for any sign of component failure.
Bend the paperclip and insert one end into the green pin PS_ON and the other into any of the black pins Ground. When testing the power supplies while running with a power supply tester or with a DMM all voltages are within the ATX voltage spec however the PWR_OK power good signal does not come on remaining at 0v. First you want to turn the power switch at the rear of the power supply to the off position. It is simple but still sourced from the AC mains rectified so as with all power supplies of this type it will bite you hard if touched.
