Looking for PG M50 Service Manual

[apotelyt]

hi,

I have a M50 that's giving out a high dc voltage on the left channel. Anyone have the service manual that will help me in trying to get it fixed. Just replaced all the supply caps.

TIA,
david

[stipud]

http://phoenixphorum.com/viewtopic.php?f=6&t=3428

[mithatcann]

hi,

I have a M50 that's giving out a high dc voltage on the left channel. Anyone have the service manual that will help me in trying to get it fixed. Just replaced all the supply caps.

TIA,
david

Hi David, Can you solve this problem? I have same problem also. Both channel in my M50 have higher than 50mV dc voltage.

[Jacampb2]

If the DC offset is still under 500mV or so, it's probably faulty/leaky differential pairs. This is pretty common in an amp that's been abused. If replacing the differential input pairs with new matched pairs doesn't remedy it, it's possible that there is an issue in the current source. I've been getting in a lot of m series amps with faulty current sources now.

If the offset is higher than ~500mV, you more than likely have a leaky output transistor. They also need to be replaced in matched pairs even if only one output failed. The output, it's compliment, and all parallel outputs must be replaced.

If you don't know what I'm talking about, then you are out of your depth and should send the amp to a qualified tech.

There are no and never have been any Phoenix Gold service manuals. There are some schematics that can be found in the public domain. All of the mid and to tier PG amps of this era have virtually the same design. The major differences were in power supply current capabilities, poweramp scale (how much output current it could drive) and preamp/crossover options.

Good luck,
Jason