"Onan" Quantar Power Supply - service manuals?!??

Ray D. O'Mann #2 · Post by **Ray D. O'Mann #2** » Sat Mar 09, 2002 3:42 pm

Ever tried blowing the dust out of a Quantar power supply while it was still powered-up? DON'T! (it goes 'POP') I guess the dust was thick enough to arc somewhere in the high voltage section, and of course, the manuals are not "available" conveniently... I don't have p/n in front of me at the moment, but it was for 20w 800mhz station. Anyone aware of a source for manuals? Or a depot other than the big M?

Will · Post by **Will** » Sat Mar 09, 2002 4:20 pm

AC line, 120 or 240 Volts AC, is the highest voltage. 28 volts DC for the PA, 14.2 and 5.1 volts DC for the rest of the radio. 14.2 volts DC for the low power PA's.

Conductive dust? It IS possible at some locations. Is'nt Onan the god of power?

redgreen · Post by **redgreen** » Wed Mar 13, 2002 4:25 pm

HAD SAME EXPERIENCE WITH SAME SUPPLIES.bLEW OUT ONE SUPPLY 1/2 HR AND THEN HOUR LATER 2ND AND THIRD SUPPLY BLEW. CHANGED OUT TWO SWITCHING Q'S IN ONE AND FIXED SUPPLY THE OTHER TWO I'LL NOW SHORTLY BUT EXPECT SAME FAULT AS WELL AS INTERNAL 7A FUSE

cracked · Post by **cracked** » Wed Mar 13, 2002 9:10 pm

common problem it seems. i learned the hard way too when attempting to wipe off a dusty quantar with a rag. motorola, at least at first, responded by placing a partial shield behind the front panel vent holes. theory is that this'll stop the capacitor shrapnel from reaching your face. it's been a while since i checked up on it, so maybe now the supplies are different. i think they may also be different on a base station vs. only receiver station (unless the only difference is a couple fans in the front).

<font size=-1>[ This Message was edited by: cracked on 2002-03-14 00:14 ]</font>

redgreen · Post by **redgreen** » Thu Mar 14, 2002 3:12 pm

It appears that only the older supplies are made by Onan. The current ones seem to be of similar circuitry but of M's manufacture.At least I have schematics for the current supplies. There seems to be only 2 versions out a 265 watt and 650 watt AC supply. The new ones doen't appear to have Onan fatal flaw. The interconnect pins are not open pins in the new supplies but are a ribbon cable. This does not leave the 400 volt DC potential separated by air gaps. It seems the right amount of dust filled the gap.

Will · Post by **Will** » Thu Mar 14, 2002 4:45 pm

400 VOLTS, just to make 28 volts DC ???????
I could see 150 DC from the rectified line voltage. (300+ if on 230 VAC).
Guess I am counting my blessings tonight, haven't had a problem there, yet.
I do not like the fact they (Moto) does not want to give out schematics on these radios.

redgreen · Post by **redgreen** » Fri Mar 15, 2002 2:16 pm

They use a switching supply for their Ac to Dc boards even in the 24/48 v dc power supplies. All cases generate a 400 v Dc which supplies the regulator board. i am still working on getting manuals though. M wants $1800 cdn. for replacement supplies without the vasaline.