iMac G5 PSU

[Kelly889]

I just replaced two caps in an iMac G5 PSU - model 614-0325. I checked the open circuit voltages and they are not the same at standard ATX supplies. In particular, there is a +24 line which I didn't expect.

I found this site by Googling for 614-0325 pinout. There's a thread with that supply as the topic and it seems that 24V is an expected voltage.

Can anyone point me to where I can find more info on what voltages to expect on what pins and how to turn the PSU on without installing it in the comptuer? I'd like to check it out before putting the PSU back in.

Thanks,

[shovenose]

Re: iMac G5 PSU

unfortunately apple had to their proprieatary shit and i dont think the normal way of shorting the green wire to black in a pc atx supply would work with your power supply...

[Kelly889]

Re: iMac G5 PSU

Thanks,

When I looked at the connector and realized that it looked like a standard ATX and that the grounds were the same, I was hopeful that it was a standard ATX pinout. However, when I saw 24 V on one of the pins, I knew different.

Still searching for the pinout and how to turn this PSU on outside of the box.

[shovenose]

Re: iMac G5 PSU

is there a green wire in the main connector? sort of near the middle in the top row?

[Kelly889]

Re: iMac G5 PSU

No green wire
- the wires are mostly black and grey.
- There are 4 brown wires and:

- blue wire in pin 7
- purple wire in pin 8 showing me +5V

Pin 14 shows +5V
Pin 20 shows +24V

[shovenose]

Re: iMac G5 PSU

so this is the standard atx pinout:
http://www.subedartech.net/docs/pc/c...atx_pinout.GIF

and im assuming your psu looks somewhat like this:
http://lh3.ggpht.com/_hsvnxFEc2do/Sf...jpg?imgmax=800


aha!
is this right???
http://www.xlr8yourmac.com/images/im...ply_pinout.gif

[Kelly889]

Re: iMac G5 PSU

Yes to all three questions.

in the first pix - it looks like v 1.0

Now looking at the third pix,
pin 8 (PG) shows 5V
pin 14 (ON/OFF) also shows 5V

I probably have to ground one of them, most likely ON/OFF to get the PSU to power up. I just don't know which one.

[shovenose]

Re: iMac G5 PSU

short the on/off to ground i think

[Quasar]

Re: iMac G5 PSU

All that info is on this forum. Try using search.

[Kelly889]

Re: iMac G5 PSU

Thanks Quasar,

I searched for iMac G5 PSU and didn't find what pins to do what with to power up the PSU without the computer.

Note: Looking more closely at the connector, I see that it's a 22 pin, not a 20 pin connector. So the pin numbers that I stated earlier are wrong. I'm using the picture in post #6 as my guide.

[Quasar]

Re: iMac G5 PSU

I think I found what you need on page 3 of this thread. There are some 25 threads on iMac power supplies.

https://www.badcaps.net/forum/showthread.php?p=78821

[Kelly889]

Re: iMac G5 PSU

WHAT A FIND!

Wow - that's exactly what I was looking for! I grounded pin 15 (ON/OFF) via a 56 ohm resister. (I don't like to ground them directly and 56 ohms is what I have hanging around.) I measured the voltages and they looked good open circuit. Put the PSU in the machine and it started right up.

Can't thank you enough.

btw: Looking at the second photo in post #6 of this thread, do you know what that silvery button is above the AC connector? I thought it might be a safety interconnect, but I don't think so because the PSU powered up fine outside of the computer.

[seanc]

Re: iMac G5 PSU

Cable lock slot

[Kelly889]

Re: iMac G5 PSU

Yeah. I see that now. Thanks.

[godonr]

Re: iMac G5 PSU

If you have AHT (AppleHardwareTest) DVD run it to verify video ram.

[marthyr]

Re: iMac G5 PSU

.