PowerMac G4 (Quicksilver) Power Supply
in [Repair]
|
Prev: JVC subwoofer problems.
Next: Toshiba TP50F60 Failure
From: Chris on 22 Jan 2006 02:10 Hi, I was curious if anyone has information on repairing a power supply for a PowerMac G4 733 (Quicksilver). I believe the supply has an issue as it won't start up the machine, but it spins the fans for a few seconds before shutting down. Any suggestions or information would be appreciated as the replacement is quite costly! Thanks, Chris
From: spudnuty on 22 Jan 2006 10:05 Chris wrote: > Hi, > > I was curious if anyone has information on repairing a power supply for > a PowerMac G4 733 (Quicksilver). I believe the supply has an issue as it > won't start up the machine, but it spins the fans for a few seconds before > shutting down. Any suggestions or information would be appreciated as the > replacement is quite costly! > > Thanks, > Chris Have you taken the power supply out and cleaned it out? I actually use a leaf blower to do this (homemade) and have recovered many power supplies like this. In lieu of that check on ebay they can be had very cheaply when compared to OEM. There's a new one there right now starting at $.99. Check the part # and see if it's compatable with your machine. Richard
From: spudnuty on 22 Jan 2006 10:18 > > I was curious if anyone has information on repairing a power supply for > > a PowerMac G4 733 (Quicksilver). I believe the supply has an issue as it > > won't start up the machine, but it spins the fans for a few seconds before > > shutting down. Any suggestions or information would be appreciated as the > > replacement is quite costly! Also you could check out: http://www.repairfaq.org/REPAIR/F_smpsfaq.html#SMPSFAQ_019 but be aware that the capacitors in switchmode supplies can be very dangerous (as noted in Sam's site). Some SMPSs won't operate properly unless they're under load, as here in the pdf. (below): "Note: To verify the power supply, you need a volt meter. When connecting the volt meter leads to specific pins, make sure the power supply remains securely plugged into its connector on the logic board." I also have the pdf. take apart, troubleshooting and pinouts for the mirrored door G4. Might be similar. Richard
From: James Sweet on 22 Jan 2006 14:42 spudnuty wrote: >>> I was curious if anyone has information on repairing a power supply for >>>a PowerMac G4 733 (Quicksilver). I believe the supply has an issue as it >>>won't start up the machine, but it spins the fans for a few seconds before >>>shutting down. Any suggestions or information would be appreciated as the >>>replacement is quite costly! > > Something worth checking out are the fans. I'm not sure if the Mac does this, but many PC motherboards will shut down immediately if they detect the CPU cooling fan is not running and will exhibit this exact same behavior. They normally use 3 wire fans and monitor the tachometer line.
From: Chris on 22 Jan 2006 16:00
Wow! A huge thanks to all of you so far! I didn't expect this many replies. Here are some more details about it. I had checked it out to see if it was dirty, and it looked pretty clean (also no charred components when I glanced around inside). I can try cleaning it out again. All the fans spool up for a few seconds before it just stops dead in its tracks. The Apple P/N: 614-0157. It appears that there are no matches for this machine out there at the moment (DigAudio, MDD, Sawtooth are all different!). Also, the fans are all two wire as well, but if they are all working anyway I wouldn't suspect that to be the issue. Another issue is that I have been told it is remotely possible that the logic board is the problem instead. That is much more expensive, and still difficult to tell which is causing this strange problem. -Chris "James Sweet" <jamessweet(a)hotmail.com> wrote in message news:AeRAf.1957$zh2.1452(a)trnddc01... > spudnuty wrote: >>>> I was curious if anyone has information on repairing a power supply >>>> for >>>>a PowerMac G4 733 (Quicksilver). I believe the supply has an issue as >>>>it >>>>won't start up the machine, but it spins the fans for a few seconds >>>>before >>>>shutting down. Any suggestions or information would be appreciated as >>>>the >>>>replacement is quite costly! >> > > Something worth checking out are the fans. I'm not sure if the Mac does > this, but many PC motherboards will shut down immediately if they detect > the CPU cooling fan is not running and will exhibit this exact same > behavior. They normally use 3 wire fans and monitor the tachometer line. |