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Gallien Krueger ML250 output issue

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pmarchione:
kinda a newbie, but i have built a few effects from kits and such.

I just aquired an old Gallien Krueger ML250 from my dad. the input jack was broken and I replaced it with no problems. The issue Im having is the output jack on one side is maybe half the volume of the other side. the circuit board look ok with no burns at any of the componet sites. it will drive a 2x12 on one side well. I have a multimeter, a good soldering iron, and some knowledge. where do I start? Pix will follow if anyone can help.

Thanx all

Roly:
Grab this;

http://www.schematicsunlimited.com/download.php?manu=gallienkrueger&file=gallien-krueger-ml-series-service-manual.pdf

...and try to identify the circuit(s) that match yours, extract them from the PDF (copy, paste into something like IrfanView, and save as a GIF's) then post here so we can all work on a common basis.

A first test is to try a jumper lead from Fx Send to Fx Return, except with this amp it might require a stereo lead, TRS (I'm assuming for the moment it's one of their "stereo" systems?).

Is the weak output channel still clean, or distorted?

If you feed in equal signals to both L&R Returns (at the same time) is one still weaker than the other? (if so it means the problem is in the main power amps, if not it's in the preamps).

pmarchione:
Roly,
Yes the is a stereo model, but according to the user manual the effects loop uses standard guitar cables so trs stereo cables are not required if I am using the effects loop. So if i understand you correctly i should connect a cable from send to return and see if the weak side is distorted or not? there are no left and right returns. there is however an aux in/stereo out 1/4 inch jack on the back also. i guess i should check to see if the signal is the same comming out of that to my pa or something huh?

pmarchione:
one more thing. there are two internal 6.5inch speakers that I just assume have equal output but it is hard to tell just by listening. I guess i could hook a multimeter up to the wires going to each internal speaker and check that the output is the same also. correct?

pmarchione:
I think I found the culprit. After testing the amps internal speakers I found that only one was working so I opened it up and  followed the path from the speaker contacts and found this burnt resistor/inductor. not sure which it is.

the green one in the center of photo one with the red/gold/black/brown bands.

Can anyone help me ID this so I can go to radio shack and order one?

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