Currently Being ModeratedNov 13, 2012 12:28 AM (in response to kazandb)
Buy replacement leads for your voltmeter.
Long, slender and sharp probes aren't uncommon.
Very sharp probes can simply pierce a wires plastic sheath to obtain a reading, but pushing said probe down into the connector along side the wire will also allow you to obtain a reading.
Currently Being ModeratedMar 21, 2013 5:20 AM (in response to japamac)
4 months later and I still haven't been able to test the PSU as you suggested...
However, I'd like to let you know of the exact symptoms I've been having:
If the computer stays connected to a wall outlet it will power up with no problem. But if I unplug the power cord and leave it for some time (maybe half an hour or more) and then plug it back to the wall the computer does not start. When it comes to this, what I do is unplug again the cord, push the power button until the light goes out, replug then hit again the power button. This last procedure often does not give immediate result and most of the times I need to repeat it 4 or 5 times until the computer starts.
Following the G4 MDD official tech manual, I first checked the PRAM battery which still has a 3.6V and is therefore valid. I also went through the PRAM clearance procedure (unplug, clear PRAM, wait for 10 seconds): The computer started once normally, that is having previously left it unplugged for some time it started immediately after it was replugged. However, it quickly went back to the situation I described in the 1st paragraph. That's all about it...
Currently Being ModeratedMay 16, 2013 12:13 PM (in response to kazandb)
Here is an update - and a closure?- of the whole story:
The computer booted normally until yesterday. Today, when I pressed the power button I got a short circuit that cut power in the room; Needless to say that the PSU is gone - I have zero readings on every attempt to verify the voltage (unless of course I keep doing something wrong). I have tried all procedures on the service manual plus additional testing as described on japamac's site. Dead. Nada.
PSU replacements on ebay roughly equal the cost of the whole machine, so I 'll probably sell everything piece by piece.
Currently Being ModeratedSep 29, 2013 5:02 PM (in response to kazandb)
There are guides on how to replace the PSU with an ATX PSU.
Or this one http://www.youtube.com/watch?v=wEzbl3eJIro (ATX PSU convertrd to fit in the original PSU's housing).
Serveral changes of the PSU in this thread http://forums.macrumors.com/showthread.php?t=1058843
There are also other thin and long PSUs, similar to the MDD PSU. If you know the wires you can tranform them.