Suspect Bad PS Apple AcBel API 1PC36

[Toasty]

Seriously doubt it's C30.

[thestitch]

Hi, Toasty !

After several days of severe testing the PSU under very
nasty thermal condition... yes, it`s rock stable again ! ! !
Put 4 (!) 15k SCSI HDs in and connected an 22" ADC Display to ATI 9800,
after appx. 90 starts no PSU failure :-)

Faulty cap was C30 in this PSU.

Thanks
willy

[Chevy2]

I have the same PSU, same symptoms, but the white 25V lead is shorted. Any ideas what I should check?

[Toasty]

Regulator.

[Chevy2]

Sorry, it's been a while since I've done any electronic components repair (other than just replacing bad caps). Do you know which one I should try to replace first or the quick process to track down the bad one? Thanks.

[Toasty]

You are stating that the 25v line is shorted. What makes you say that?

[Chevy2]

Looks like the 25v was me and some bad soldering. That part is fixed now. I get 5v trickle and 25 volts, but no trickle 12 v like I should per the link below. I have one 2200uf that looks fine, that I haven't replaced yet, should I go ahead and change it out too? The PSU fans spin and turn off when I push the power button.

http://www.jcsenterprises.com/Japama...EB2C04619.html

[Toasty]

Best read that pinout again.

[Chevy2]

Looked it over again. They made it sound like the 12v was a trickle. Since the PSU fans spin up and quickly turn off when pushing the power button (motherboard lights up too) and I have 25v and 5v trickles, which caps would you recommend replacing next?

The motherboard boots fine btw. I tested with a PC supply and an adaptor that I made.

[Toasty]

See Posts #11 & 119.

[Chevy2]

Thanks Toasty...appreciate the help!

[Chevy2]

Originally Posted by Toasty

See Posts #11 & 119.

Toasty, thanks for taking the time to help me out. C43 and the secondaries were the issue and it's working perfectly now.

[Toasty]

Great! Was just going to ask how you made out. Glad you got it working!

[stevenA]

Thanks to all of your posts (especially Toasty and his lessons) I have just recapped a G4 MDD PS and solved the long running problem that it would only start with an ADC display connected.

For info, the bad caps were:

C16
C21
C29
C43
C60
C32
C45
and maybe C30 which was out of limits for my tester.

Said otherwise, all of the Teapo's removed had failed, and some of the L-Tec's. I suspect that the start up problem was linked to C32 or C45, although this is only a suspicion - either way, they all needed replacing as smoothing caps can cause bigger issues in the long term!

Thanks again

[stevenA]

Originally Posted by stevenA

Thanks to all of your posts (especially Toasty and his lessons) I have just recapped a G4 MDD PS and solved the long running problem that it would only start with an ADC display connected.

For info, the bad caps were:

C16
C21
C29
C43
C60
C32
C45
and maybe C30 which was out of limits for my tester.

Said otherwise, all of the Teapo's removed had failed, and some of the L-Tec's. I suspect that the start up problem was linked to C32 or C45, although this is only a suspicion - either way, they all needed replacing as smoothing caps can cause bigger issues in the long term!

Thanks again

After finishing the job and testing, I QC'd the components used and recorded actual results - as you will see in the attached, I actually used the wrong component for C35 - I had intended to use a UCC KY but had multiple caps and made the mistake. Hopefully should not be critical as this is a smoothing cap