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Old 04-26-2021, 11:12 AM   #2
PeteS in CA
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Join Date: Aug 2005
City & State: San Jose, CA
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Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
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Default Re: Apple G4 AcBel PSU - blink failure mode

Some generic questions:

* Does this P/S have active PFC? If it does, what is the voltage across the big electrolytic capacitor? If it does and that voltage is ~165V, the PFC is not working and that is where to start your troubleshooting.

* If it does not have active PFC or the voltage across the big electrolytic capacitor is something like 390V, do you have good 5V Standby? If not that is where to start your troubleshooting. If 5V Standby is also OK, then the problem is in the main inverter or output circuits.

I'm not familiar with the specific power supply, but these are quick ways to localize where to look for problems.
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