Rockola 44790-A amplifier

stangbat

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This 44790-A amplifier is in a Rockola 440. The problem is the left side outputs nothing, not even any hum when unmuted. I measure nothing directly from the amplifier outputs, so the problem is not with the speaker distribution or speaker connections at the back of the jukebox.

I have a manual and schematics.

What I've done so far:
-Tested and swapped the output transistors, no help, the left side still doesn't work and the right side does
-Checked continuity for the left drive transformer, it appears fine and measures the same as the right.
-Checked various voltages at the transformers, output transistors, the bridge rectifier, and didn't see anything that looked funny
-Tested continuity for the dual lamp Barretters, they are fine
-Tested and compared whatever transistors I could, all appear fine
-Swapped the R/L at the cartridge, still nothing from the left, so the cartridge isn't the problem
-Visual inspection of all components, nothing looks bad, no evidence of magic smoke. I probably need to look a little closer for cold solder joints though.

I'm not real savvy with amplifiers and I think I've run thought the obvious easy stuff. Any suggestions or pointers are appreciated!
 
Sounds like you've checked just about everything.

I recall someone on this board who use to fix Rockola's but I can't remember their username.
 
Can you verify the muting circuit is turning off?
Maybe one side isn't tripping when it should.

Just an idea...

I'm finally back to poking around on this. The muting relay itself is working fine. I pulled it, put power to it on my bench, and all contacts were fine.
 
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