Was given this PSU from someone when it stopped running their machine.
Symptom was that their Asrock motherboard would not POST (onboard status LEDs said FF) but worked with another PSU. Weird thing was, the PSU ran fine in a machine I had, but not another. All voltages tested normal.
Found that the Power_Good\PS_OK signal was not present. Guess one of my PCs doesn't care... FF error made sense now, his board was being held in reset state. Anyway...
Check inside, found monitor IC a PS224 (see datasheet).
No signal direct from Pin 16. Checked all other pins. All seemed OK or I was unsure but PGI Pin 1 obviously wrong at 0v, should be 5v going by example circuit.
Traced back Pin 1, ends up at 12v rectifier output. Found burnt diode and resistor D308 and R315.
Checked all other components between R315 and Pin 1 for shorts but found nothing.
Any ideas why D308 and R315 burned? Any ideas on replacements? R315 I'm guessing is 10 Ohms, don't know about D308.
Symptom was that their Asrock motherboard would not POST (onboard status LEDs said FF) but worked with another PSU. Weird thing was, the PSU ran fine in a machine I had, but not another. All voltages tested normal.
Found that the Power_Good\PS_OK signal was not present. Guess one of my PCs doesn't care... FF error made sense now, his board was being held in reset state. Anyway...
Check inside, found monitor IC a PS224 (see datasheet).
No signal direct from Pin 16. Checked all other pins. All seemed OK or I was unsure but PGI Pin 1 obviously wrong at 0v, should be 5v going by example circuit.
Traced back Pin 1, ends up at 12v rectifier output. Found burnt diode and resistor D308 and R315.
Checked all other components between R315 and Pin 1 for shorts but found nothing.
Any ideas why D308 and R315 burned? Any ideas on replacements? R315 I'm guessing is 10 Ohms, don't know about D308.
Comment