Vintage Synth Explorer Forums

Hey guys. I recently discovered that the right stereo output and both individual outputs don't work properly on my R-70. The right output is really quiet and the two individual outputs are even quieter and hum.

Does anyone know how I could fix them?

Surely a dying op-amp (the usual thing).I'll check my document and I'll come back to you.

I am going ask a really dumb question.......did you go thru the external mixer it has and put everything in stereo and check the volumes...I'm assuming it's set up like the r5 and r8

Yeah, I have checked the internal (thats what you meant right?) mixer. I have every thing at full volume. Thanks for the suggestion though.

Assuming that eveything outside the R-70 works as they should: mixer board, cables, amp., and that the jacks are not as loose as a crack w***e, the problem can come from IC2 (uPC4570C)- which drives the 3 outputs. But it is also possible that there is another problem along the chain. Because each outputs are driven their own digital transistor (DTC343TK). Note: it might the parts themselves that are going south. But it is also possible that they are not properly fed - which means that the problem comes further up (like bad voltage, etc).

Thanks for the reply Maschinegeist. Do you know where I can find a service manual for the R-70? With it I might be able to open it up and pinpoint the problem.

Hellhound wrote:Thanks for the reply Maschinegeist. Do you know where I can find a service manual for the R-70? With it I might be able to open it up and pinpoint the problem.

Check my signature closely: I have it, complete & clear & in PD. Please refer to the list. You can also see my website "the Boutik" section.