PowerMac G4 MDD PSU?

#1 Sat, 7 Apr 2012 - 17:43 68kMLA

Hi

I've stopped collecting macs a while ago, because i was running out of space.

Untill previous week, when i friend offered me a PowerMac G4 MDD (Dual 1Ghz) for free!

I couldn't resist and accepted, it had been running a server for sometime so i expected it to be in good condition. When ik got it home i plugged it in and everything seemed to be working fine.

Today i was going to give it a fresh install, clean it up a bit etc. However it wouldn't start anymore xx(

I tried PMU reset without succes. When i press the power button nothing happens... After some googling i discoverd they had weak PSU's (API1PC36).

I guess the PSU died? Replacing it seems expensive (ebay suggests prices lik € 80 and up).

Anyone had the same problem?

Any suggestions?

#2 Sat, 7 Apr 2012 - 21:50 68kMLA

Before doing more, I'd try pressing the PMU reset button. It's a small button near the CD cable. Then try the power button.

If that doesn't do it, then most likely a bunch of capacitors have failed in the power supply. Odds are that if you opened it up, you'd find a number of bulging caps.

I've been given a few MDD after their power supply has failed. Just recently I went to power up an early MDD only to discover that the power supply had expired.

If the eBay power supply is a pull then it can fail tomorrow. On the net you can find companies that'll rebuild your power supply. Another option is a ATX conversion

#3 Sat, 7 Apr 2012 - 23:36 68kMLA

The MDD is notorious for its power supply; there was even a service bulletin about it. Mine ended up letting the magic smoke out about a year ago, so now I have several spares (sorry, won't sell them -- I need to keep this machine running for Classilla). There is argument about which is less failure prone (there are 360W and 400W versions); it was a 400W that failed in mine, so maybe they both suck. 8)

It's a shame because the MDD is otherwise a great Mac.

#4 Sat, 7 Apr 2012 - 23:48 68kMLA

It's usually the Samsung ones that fail the most, as well as the 360w ACBel. The 400w ones are pretty good, but some do fail.

The 400w AcBel in my MDD works great.

#5 Mon, 4 Mar 2013 - 19:34 68kMLA

Sorry to resurrect an old thread but I wanted to make sure this got noted for posterity:

I revived a Samsung PSU from a Dual 1GHz MDD by replacing three capacitors:

C135 - 56uf 35V

C137 - 56uf 35V

C141 - 47uf 25V

All three are located in the middle of the board underneath the heatsink.