Repairing ACBEL Imac G5 20" supply getting hot Model 3PC96

[dmanshep]

Hello ALL!!!

So I love your site and the information here.. I am attempting to repair my imac g5 20" PSU .. It was powering down durring boot and found that one cap was bad.. so I replaced it.. now it's working much better however.. there is a small donut looking thing wrapped in black wire that is getting extremely hot.. as in melting the solder point around the base of it.. any thoughts on what would cause this? or potential troubleshooting steps I could take? See attached photo...

Thanks in advance,

Dan

[Toasty]

Re: Repairing ACBEL Imac G5 20" supply getting hot

Please provide your location in your forum profile.

Per the photo, the model number is API3PC96 or just 3PC96 for future reference. I've asked the admins to correct the thread title.

The "hot coil" issue has been addressed before and most likely it will need replacement. It's caused by the bad caps and by time most get around to replacement of the caps, the coil is damaged. Usually shorted through the insulation to the core. When they come in looking like this, I replace the coil right off.

Is it getting hot just sitting there, jumpered on, and not connected to computer? (no load)
Or, does it only happen when connected to the computer. (loaded)

You can't just replace 1 cap in these. The complete supply, sans the mains caps, needs to be recapped.

Toast

[dmill89]

Re: Repairing ACBEL Imac G5 20" supply getting hot

Please provide your location in your forum profile.

Per the photo, the model number is API3PC96 or just 3PC96 for future reference. I've asked the admins to correct the thread title.

The "hot coil" issue has been addressed before and most likely it will need replacement. It's caused by the bad caps and by time most get around to replacement of the caps, the coil is damaged. Usually shorted through the insulation to the core. When they come in looking like this, I replace the coil right off.

Is it getting hot just sitting there, jumpered on, and not connected to computer? (no load)
Or, does it only happen when connected to the computer. (loaded)

You can't just replace 1 cap in these. The complete supply, sans the mains caps, needs to be recapped.
Toast

I'll second that. The fact that the wire is black is a very bad sign since they generally come from the factory copper color the black comes from overheating and burning the lacquer coating. At this point it is best to just replace it. The small cap at the base of that coil would definitely be suspect, it is too small to visibly fail (bloat or vent) but could have failed internally causing the coil to overheat. I would definitely replace all caps feeding that coil and would recommend replacing all the caps in the PSU except for the main as Toasty suggested. Depending on age and brand I might replace the mains too just for insurance since it isn't that much more work if you're already recapping the PSU, Just make sure they are drained first.

[dmanshep]

Re: Repairing ACBEL Imac G5 20" supply getting hot

Ok.. so this is great feedback.. as for buying the parts.. I have found cap kits on flee bay.. however how would I find the correct coil?

thoughts??

[Toasty]

Re: Repairing ACBEL Imac G5 20" supply getting hot Model 3PC96

>>The small cap at the base of that coil would definitely be suspect, it is too small to visibly fail (bloat or vent) but could have failed internally causing the coil to overheat. <<

Except that, that small cap is not part of the coil's circuit.

[dmill89]

Re: Repairing ACBEL Imac G5 20" supply getting hot Model 3PC96

>>The small cap at the base of that coil would definitely be suspect, it is too small to visibly fail (bloat or vent) but could have failed internally causing the coil to overheat. <<

Except that, that small cap is not part of the coil's circuit.

sorry, never actually worked on that specific model PSU or seen a schematic for it, just inferring from the pics. Either way any caps in the circuit definitely need replaced and as others have said its probably best to replace them all.