On 5/21/10 1:23 AM, Mac User #330250 wrote:
Hello G-Group Readers!
I have a problem with my G5 “Late 2005” 2.0 GHz Dual-Core Power Mac. About two
months ago, as I was switching it on, I heard a loud BANG and only silence
ever after. It plays dead ever since, I don't even hear the click when
plugging it in.
I figured the PSU must have died, most likely due to a blown condensator. But
I'm not 100% sure.
That would be a CAPACITOR. The old name for them is CONDENSER. If you
had a CONDENSATOR in the power supply that would be a problem, it is
something that condenses water out of the air.
Since a new PSU is>150 $ (710 W as well as 1000 W) and most of them are in
used condition, I figured I might as well try to fix the broken one I have at
hand.
It took me a while to figure out how to get the PSU out of the case, and now
that I finally got to it, I find that there is no visible defect inside the
PSU.
*So my questions are:*
If a condensator actually did blow up, shouldn't it be a visible defect?
It won't always be visible. Sometimes the blow out occurs on the side
next to the PC board so it is hard to see.
You can try removing each capacitor in turn and visually inspect it.
Then try replacing any that look bad. IF you have a good source they
won't cost you that much but getting a replacement that fits may be
difficult.
It's possible to test them but as you stated elsewhere you don't know
how to use a multimeter so testing caps is not really an option.
If not so, how am I gonna find out where the fault is?
Or even worse, if the loud BANG didn't come from the PSU, but from the system
board or…<I don't know what>, how can I test if the PSU is in working
condition without it being connected to the Power-On button?
If it came from other than the PSU or logic board you can just
disconnect everything but the PSU and start button from the logic board
and try it. You can't do anything but you can see if it starts up.
But the BANG implies it is the PSU or perhaps the logic board.
Many switching power supplies can be destroyed by operating without a
sufficient load so don't try testing the PSU without the logic board
attached.
Switching power supplies are difficult to test as there are many
components whose failure can cause the PS to not function in exactly the
same way. Also there is high voltage in there and you don't want to
mess with that if you don't know what you are doing.
Since I'm stuck right now, I rely on your experiences and knowledge here in
the G-Group. Otherwise I don't know what my next steps have to be. And I don't
want to trash/sell/abondon my G5 – I want it back!
Look on e-Bay for either a PSU or a G5 , particularly one with a logic
board problem but a good PSU.
Make sure the supply matches your computer. I don't know if the G5 has
different incompatible power supplies or not but if it does you don't
want to make matters worse with the wrong unit.
--
Clark Martin
Redwood City, CA, USA
Macintosh / Internet Consulting
"I'm a designated driver on the Information Super Highway"
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