Dr Synth DS-330 noisy output

I have a BOSS Dr. Synth DS-330 module that has, unfortunately, developed a lot of noise and hum on its output. I was hoping to attempt a repair but cannot find the schematics for this thing anywhere. Would anyone out there have them?

Thanks in advance!

Any suggestions as to how I might get this thing happy again?

check op amplefires voltages and also check DAC IC.

I will see what I can find out. No schematics for this one, so I’m flying a little blind.