Re: IMAC 24" PSU #614-0387 - Bad Caps replacement

Power supply 614-0387
When it gets hot, you have to unplug it to get it to start up again.
When cool, it always starts up and runs fine. Sometimes if I leave it on for a few days, it will shut off by itself.

I know these power supplies are cheap on ebay, but I'd like to know if it's an easy fix.
I can buy these imac's CHEAP and would like to fix them for a profit.

Usually, it's the startup caps, C131, 132 - 33uf 35V 105° green Taicon, but these check fine, .5 ESR, most of...

Power supply 614-0387
When it gets hot, you have to unplug it to get it to start up again.
When cool, it always starts up and runs fine. Sometimes if I leave it on for a few days, it will shut off by itself.

I know these power supplies are cheap on ebay, but I'd like to know if it's an easy fix.
I can buy these imac's CHEAP and would like to fix them for a profit.

Usually, it's the startup caps, C131, 132 - 33uf 35V 105° green Taicon, but these check fine, .5 ESR, most of my other new stock are at 2 ohms or worse.
I think these are low...

Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start

Complete recap, same problem.

Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start

33UF 35V (130°) X2 - 1.0 ohms - RX30
100uf 35V - 0.5 ohms - (PW)P
220UF 35V X2 - .25 ohms - (HD)P
820UF 25V - .25 ohms - ZLH
470UF 16V - .25 ohms - (PW)P
1000UF 16V X6 - .1 ohms - ZLH
150UF 50V - .25 ohms - ZLH
120uf 450V X2 - .25 ohms - BXA

Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start

I took the power supply out.
I had to cut the heatshrink off the 2 33uf 35V caps with a sharp exacto knife.
I found the following ESR values:
33UF 35V (130°) X2 - 1.0 ohms
100uf 35V - 0.5 ohms
220UF 35V X2 - .25 ohms
820UF 25V - .25 ohms
470UF 16V - .25 ohms
1000UF 16V X6 - .1 ohms
150UF 50V - .25 ohms
120uf 450V X2 - .25 ohms
All caps are RubyCon 105° caps, except the 33uf 35V ones.

Seems like they are all...

Slight click when power button is pressed, HD spins up for 1/2 a second, then shuts down. Obviously, it is trying to power on, because the HD spins up for a 1/2 second. I don't suspect any shorted diodes or semi's. I do not have a schematic, or I could do the troubleshooting myself. Please feel free to be very technical. I have an ESR meter, and a Hakko 880 de-soldering machine.

This is a 240W power supply, and has been replaced with a newer power supply, the APPLE 661-4478, an almost identical 250W version which includes a "pressure wall" which probably has to do with...

Re: New Members - please post your introductions here

Michael Kinnaird, 43+ years audio/video bench tech for Pacific Stereo, IAV/Home Entertainment, Tweeter, Etc., and 7 years with GeekSquad. ISF certified calibrator, ISCET cert., Member I.E.E.E
I repair ALL brands of TV, RPTV, FPTV, plus OLD Apple II, IIGS, Mac, iMac's, and Mac Pro monitors and computers.