M44 overloading Help!!

[Eric D]

I think you have a ground problem with the front channels. The inside terminals should both read 0 ohms to the inside terminals of the rear set of terminals (all 4 wires go to the same place on the board).

Did you use the same speaker and wire for the testing of the channels separate, and bridged?

[vegasrich77]

Yes, I did use the same speaker and wire for both separate and bridged test.

I am a little confused on what you are saying about the 0 ohm of the inside terminals. Are you talking about the left negative and right positive for each side? Do you want me to messure from the front left negative to the rear left negative or the front left negative to the front right positive? They both come up as 0 ohms.

[Eric D]

Look at the area I circled.

Those 4 connections all go to the same spot on the board. So, out at the terminals, you should be able to measure 0 ohms from any of them to each other. These are the output grounds.

Since your amp works when bridged, but goes into overload when not, you may have a problem with the grounds.

By the looks of your drawing, you are understanding what I am talking about. You should also be able to get 0 between the inner terminals on the rear section as well.

When you bridge the amp, does it sound good?

[vegasrich77]

Yes, I did notice that the sound was not that clean and clear.

[Eric D]

I think you have a bad channel then.

[vegasrich77]

Is it hard to fix? Are the parts even available?

Eric - Thank you very much for your help!!!

[Eric D]

Well, I don't know where to begin to explain fixing a channel. I just fixed a M44 and it took me several hours to track down one bad resistor and one bad transistor. These amps fail in different spots, so it is a matter of working your way through the circuit to find the issue.