In a message dated 8/21/02 8:06:11 PM, [EMAIL PROTECTED] writes:
<< I've checked all the sites for troubleshooting, too. I wanna fix this thing; not replace it, but I need to know WHERE to start looking for the problem. Is it probably in the main transformer, or should I give scrutinty to the rectifier? >> Most PSU problems are in the primary side, with the bridge rectifier being one of the main failure points. Since the Q (and most other Macs of that era) are auto-switching, you will find a relay, a bridge rectifier (or four separate diodes) and two large electrolytic caps. When in 240 volt mode, the primary side acts as a full-wave bridge and outputs about 340 volts into the flyback transformer. When in 120 volt mode, the peimary side acts as a full-wave voltage doubler, and also outputs about 340 volts into the flyback transformer. Either way, the inverter sees about 340 volts dc, and outputs various voltages including +5, -5, +12, -12, etcetera. -- Quadlist is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> Quadlist info: <http://lowendmac.com/lists/quadlist.shtml> The FAQ: <http://macfaq.org/> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/quadlist%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
