Failure mode of Apple G4 MDD PSUs ?

[Agent24]

I've recently acquired a PowerMac G4 MDD which I had some trouble starting, and although I think the problem was actually to do with a RAM stick, in my research I found out that these are known to have PSU problems - so I think I want to look into that as well, even if just for fault prevention.


My question is, what is the problem with the PSUs used in these? Just usual bad capacitors or something more?

I've got an AcBel, API1PC36 Rev:B (see attached photo)

[Toasty]

Re: Failure mode of Apple G4 MDD PSUs ?

The search tool is your friend....

https://www.badcaps.net/forum/showthread.php?t=13985

https://www.badcaps.net/forum/showthread.php?t=14077

The AcBel's are usually just caps. A few small ones and the outputs.

The Samsung's can be quite a bit more involved, but their output caps are generally sound. The mains cap, main switcher MOSFETs and the little caps are what gets you on these.

[Agent24]

Re: Failure mode of Apple G4 MDD PSUs ?

Thanks, in fact i did find those after I posted

However, they talk about totally dead PSUs... mine seems to be working OK - no startup problem since cleaning the RAM contacts anyway...


I might open mine up and check the capacitors when I find time...

[Toasty]

Re: Failure mode of Apple G4 MDD PSUs ?

No problem!

Post back if you need assistance with the caps.

Toast