Apple G4 AcBel PSU - blink failure mode

ChairmanJones · 04-24-2021, 04:42 PM

I have an AcBel PSU that was exhibiting the typical failure mode with the single blink light then no power on.

I started the rebuild with the shotgun 12, same issue. Fuse has continuity. My question is, has anyone narrowed down the cause to specific caps or is it a case of replace them until it works? What caps should I be replacing next?

**PeteS in CA** · 04-26-2021, 11:12 AM

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.

04-24-2021, 04:42 PM	#1
ChairmanJones New Member Join Date: Apr 2021 City & State: Fenton My Country: United States Line Voltage: 120VAC 60Hz I'm a: Hobbyist Tech Posts: 2	Apple G4 AcBel PSU - blink failure mode I have an AcBel PSU that was exhibiting the typical failure mode with the single blink light then no power on. I started the rebuild with the shotgun 12, same issue. Fuse has continuity. My question is, has anyone narrowed down the cause to specific caps or is it a case of replace them until it works? What caps should I be replacing next?

04-26-2021, 11:12 AM	#2
PeteS in CA Badcaps Veteran Join Date: Aug 2005 City & State: San Jose, CA My Country: USA, Unsure of Planet Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz I'm a: Professional Tech Posts: 3,491	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. __________________ PeteS in CA Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells. ************************** To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it. ************************** Anti-Covid-Vaxxer pig crap claim/prediction, Doctor: Heart Failure from mRNA Jabs "Will Kill Most People" \| Principia Scientific Intl. ; Dr. Geert Vanden Bossche Warns COVID-19 Jab Injuries and Deaths Will Soon "Collapse Our Health System" (VIDEO) ; Fully Vaxxed May 2021; Since that time I've done 10 5Ks, 1 8K, 8 10Ks, and 4 half marathons

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode