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Old 6th November 2012, 09:46 PM   #1
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Default Dean Markley rm-80-dr

I recently acquired a position repairing amplifiers for a music shop in Massachusetts on a sub-contract basis. I was given a Dean Markley RM-80-DR to troubleshoot a matter of weakened volume on the top channel.

I have looked everywhere for this schematic. I even asked the manufacturer.

Does anyone have it that would be willing to email it to me or better yet post it?

Also, has anyone else experienced this issue? If so, how did you solve it?

Maybe this amp's circuit is the same as another similar model that I could find?

Please help...thanks, Twombstone
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Old 6th November 2012, 10:59 PM   #2
Enzo is offline Enzo  United States
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Location: Lansing, Michigan
This DIY board is a fine forum, but if you are going to be doing amp repair, I think you need to visit a few more that are more focused on instrument amps rather than hifi.

Try this one for general coverage, and note they have a schematics request section on the menu. Post your needs there.
Music Electronics Forum


A smaller board that concentrates on solid state:
Solid State Guitar Amp Forum | DIY Guitar Amplifiers - Index

If I have that schematic I'll post it. I'll have to look.
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Old 9th November 2012, 02:51 AM   #3
Simon B is offline Simon B  United Kingdom
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Location: North-East England
The pic attached has been posted on here in relation to a previous query. It's only a fragment, but something to start looking at.

Sometimes fate smiles after all ........ I have to say that, after putting a scope probe across the tremolo neon in a twin reverb showed me exactly the snubber circuit to use to stop it clicking audibly....about 30 secs after starting work.

Good luck
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Old 16th November 2012, 05:27 PM   #4
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Clean the controls.

Then check the J-FETs that are used for channel switching.

Next likely would be cold solder joints. Be careful, the pads will lift off of this board if too much heat is applied.

If you've downloaded that schematic link that was posted on ME forum, you will see that most parts of the amp are common, including the tube.
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