Ads pq10

[mike49504]

I got this amp in for repair.

When powering it up it draws excessive current. SO i unplugged the output board from the power supply board and amp idles fine.

I checked the outputs all seem fine. Wondering where i need to check next.

[tsmith1315]

Driver IC.

[mike49504]

Ok had the modle wrong pq10.2

Which one is the driver ic?

[1moreamp]

That amp is so old even I would need a internal pic to tell you where and how to roll on this one.
Plus Tim is most likely remembering the PQ amps that I remember which used UPC1270AH or UPC1225 driver chips for each channels set of outputs. I recently did a channel repair on a Alpine using these and everywhere wanted $12.00 each for a $2.25 part. I am guessing due to their age and lessening availability. Glad i found my private NOS stock pile from yester-year...
By chance have you ohmed the outputs yet, or does this amp use large STK modules. ADS did use these way back a very long time ago on their Power plate series as I recall.
Plus I do recall some of these PQ amps being 12 volt powered and not using a switching power supply at all and these were all bridged discrete device channels as I recall also.

Your asking a lot mike with out posting a snap or two of the inside to jog a old timers memory Give us a hint if you could of what it looks like please ? I have been in all of them but the I am drawing a blank with your model number duh ...thx...C

[mike49504]

Heres the pics as requested.

The IC'S in it are

UPC1270H

NJM5532SD

C1237HA

I tested the outputs on ohms setting all test good

[Perry Babin]

Clamp the transistors to the heatsink, connect your meter to one of the emitter resistors and power up the amp. Find the emitter resistor that has more than ~0.000v DC across it. That will show you the channel that's passing too much current.

[tsmith1315]

I can post a schematic tomorrow PM for the PQ10.

[1moreamp]

Perry and Tim are correct Mike. The UPC1270 is your channel driver, and they fail and usually so does a output or two. Should not be too complicated for a tech like yourself ..thx for the pic, it all came home right away...

[tsmith1315]

Here's the schematic that was included with the PQ10's manual. From your pics, the PQ10.2 looks close enough.

Print quality was poor as supplied by A/D/S, I can barely make some of it out with reading glasses on the original.

[mike49504]

THanks Perry,1moreamp,and Tsmith for the help ill order the parts and replace the defective ones.

I also found the UPC1270H for $2.24 each