Very sad news Condolences to his family and friends. I worked with Aleks for 16 years at PG and he was a great guy.

I think Jerry DesMazes built the show cars back then.

Measure voltage across the output emitter resistors (the big ones near the output transistors) and adjust the yellow trim pots to 50-100uV (not mV). Make sure the amp is cold and no input signal or load connected.

Do all the red bias LED's light up? 2 per channel, 8 total. If any are out, the LED's themselves have been known to go bad. Measure across with a diode checker, they should light up. Are the output transistors active? If so, check the bias and compare to the known good channels. If not, ohm out all ...

I bought a Contour ROAM last x-mas for $89 for my dirt biking and love that thing. Easy to use and the picture quality is amazing.

99% sure that was done at the factory. They didn't powdercoat the inside of the heatsink where the big transistors attach to it, which is good. Most people powdercoat the whole thing.

Newer PG amps with the barcode on the serial number go something like this: first 4 digits are the model, middle 5 or 6 digits the gregoran calendar date, the last 3 digits are the number of units built that day.

Its been 5+ years since I worked on those amps and now that I thought about it a little more I believe the official spec is 50uV, not 100uV. The only PG amps that idled at ~3A were the ZPA's.

Bias on MS/MPS amps is 100uV (not mV) measured across the big grey output resistors with the amp cold and no load or input signal. Your amp should idle at ~1A.

There were several custom MS/MPS/MAC amps back in the day. One local guy had 5 MS275's in one heatsink.

The 10A fuses were supposed to protect the power supply in the event of a catastrophic channel failure. In real life I don't think they ever worked as intended. When the MPS2500 is run in a rediculously low impedence those fuses would sometimes open up when the amp was working fine, just drawing a s...

A transistor in the remote circuit is shorted. Its near the fuse and either a ZTX749 or MPS750, iirc its labelled Q2 on the PCB.

Jacampb2 wrote:I apologize, I just checked one of my zx500s and valeks is correct. Earlier I just checked the schematic-- must have been a misprint, but the one I have does show 100k.

They were originally 100k, then got switched to 100 ohms as part of the V2 update.

Not much help here but the X1200.1 can be and is usually a very difficult amp to repair. The 110V rail is correct. You could try removing all of the output FET's and power the amp up on your current-limited supply. If it powers up and seems to be OK it could be the output FET's and/or damaged IC's o...

There is a transistor in the remote circuit near the fuse that is probably shorted out. Don't remember the reference designator (Q2?) but it should be a ZTX749 or MPS750.

I'd go with the RSD.

Ti600 is an awesome amp but not much heatsink. If you load it down and pound the crap out of it, it may kick into thermal protect quickly and often.

Try setting the amp crossover switches to bypass and see if the noise goes away.

That is majorly damaged. Looks like someone hooked up the power backwards and blew the crap out of the power supply. Getting a new circuit board for $250 might not be a bad option.

When the ZX's first came out the fan was only secured at 2 points, and not diagonally but on the same side. There were many customer fan failures, most likely caused by vibration (amp mounted on sub box, etc.) and poor mechanical design. The V2 fan is secured at all 4 points and is more durable iirc...

Thanks for the help guys, but I backed out of this one due to the seller becoming hasty with me requesting clear pictures of the fets. He claimed to have over 10 years experience in used car audio, sorry but that's not convincing enough to sell me an amp with no known history of what has been repai...

They are 15V supply dropping resistors. Stock value is 91Ω, the pic w/ doubles are 2x200Ω in parallel, which is 100Ω.

I finally got hired on permanent at my new job last week and celebrated by buying a new (to me) dirt bike, '03 Honda CR250.

IIRC when one of the rail fuses opens up it throws a bunch of extra voltage across that cap and KABOOM!

Wow!!

Congrats and g/l Mo.

I believe, and don't quote me on this, repairs are still done on location but the repair staff is no longer PG full time staff, but contracted instead. That is correct and would be me :) PG 12V has been officially sold to AAMP of America as of July 20th. Rodin will continue on in Portland with Audi...