Roland R-70 Low Output Except on Headphones

I recently got a Roland R-70 to play around with. The output from the headphone jack is very loud and distorts if the volume slider is higher than maybe 1/10th of the range. At the same time, all of the output from the Stereo and Individual outs is incredibly low, even if the slider is maxed out. I saw a post on modwiggler ( that describes a similar issue, but with no solution. I tried replacing the caps after the DAC, as suggested at the end of the thread, but it didn’t seem to change anything.

Does anyone here have any insight into what I could look at next? (I did check that the volume of all the “instruments” is set appropriately in the machines settings)


I’m going to guess its a failure of IC2 because the volume is a direct feedback on that IC.

Seems to be a common problem with the unit. However if you can test the output of each op amp from IC40 and IC3 to see if any sides of the op amps have volume differences. If not then perhaps a tantalum cap is hiding in there that is shorting the circuit.

I replaced IC2 (4570C) with a 4562D and the problem remains. As far as I can tell, the op amps should be equivalent in this application, but I am very much learning as I go, so feel free to correct me.

I will start looking at voltages, but I just wanted to say that your comment was still very helpful and what I am looking at in the circuit diagram make a bit more sense now, so thank you.

It does look like the problem might be in the surface mount capacitors. I don’t have any experience working on those yet, but since this thing is kind of a door stop at the moment, I am starting to think about taking a crack at it. Does anyone have any suggestions/tips for that?

Even before that, I suppose, what is the best way to figure out what they are? They are not listed on the bill of materials in the service manual as far as I can tell.