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Marantz 1070 problems

goldswimmerb

goldswimmerb

Failed out of engineering, but look at me now!
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Hey guys, so I picked up a Marantz 1070 from an estate sale. The unit seems very clean on the inside. I've already tried cleaning the controls and have been poking around in the preamp circuit.

The amplifier works just fine, when I run through the AMP IN bypassing the preamp it works just fine, so I know it's the preamp. Everything seemed to check out in the preamp circuit as well. Is there anything between the inputs --> preamp --> tone board --> power amp?

Any help is appreciated!
 

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Use a set of RCA cables jumping the main amp to pre amp to see if it will work. The jacks may need cleaning, or just jumpers installed..
 
petehall347 said:
tape monitor might cause it .
Click to expand...

Out of curiosity I swapped out the left and right on the balance potentiometer, it looks like only half the pot is working, as both channels are working before they get to the balance knob. Unless there's something after it, hard to tell from the schematic.
 
What did you use to clean the slider?
Fader lube I hope.
Also there is a control Mode that switches the channels, it may be dirty.
 
Oerets said:
What did you use to clean the slider?
Fader lube I hope.
Also there is a control Mode that switches the channels, it may be dirty.
Click to expand...
It was deoxit fader, which I figure is similar enough, made no difference.

As a test I've gone ahead any bypassed the balance knob all together, and the preamp works just fine, confirming my suspicion. I'm going to try and see if a balance fader from a 22xx works alright as the one from the 1070 seems to be unobtanium.
 
Also, how do you guys remove the faceplate hex bolts? They seem to be overtightened on this unit so my usual trick of using pliers wrapped in something non abrasive won't work.
 
A socket or boxed end wrench.
KEEP FROM TOUCHING THE PANEL!

The value if being the same then one from another model will do.
 
Any reason why R765 would flame up? Keeps burning out and I've checked my work and nothing seems off
 
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