Re: iMac G5 17' ALS Aus psu

PSU repaired ! imac is working fine now. Toasty was right to say it must be cross loaded. I still don't know what are the classic loads but I can tell you the following to summarise my findings:
- PSU was repaired by replacing 2200uF and Q1 (1P)
- full secondary side recap was done to avoid later capacitors issue
- my PSU (PI4PC46-290) is not working with no load (overvoltage protection), minimal load is 100 ohms on 5V output (50mA load).
- I replaced R95 (62 ohms) 5V output load by 33 ohms in order to have permanent internal...

Re: iMac G5 17' ALS Aus psu

Thank you Toasty for your fast reply. PCB is API4PC46-290 03L66-000
Do you need a picture of it?
Do you know what a typical cross load is for a 20" imac g5 ?
Anyway I will plug it back to the iMac tomorrow and see what happen !
I think I won't dammage the mother board electronics with under voltages.

Tim

Re: iMac G5 17' ALS Aus psu

hello everyone,

ubermoo, did you finally fixed your PSU?

I started to fix an ACBEL 20" PSU PN 614-0326. Firstly recaped (secondary side), I had a bumped 2200uF bad cap (on 3.3V circuit), I measured 650uF only. All other caps where replaced but measured values were OK:
3200uF - 3140uF
1200uF - 1245uF
1000uF - 945uF
1000uF - 990uF
1000uF - 950uF
1000uF - 930uF
1000uF - 920uF
330uF - 355uF
120uF - 127uF
However, I also found Q1 slightly burnt, so I replaced...