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!
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!
