I just received the Boss DR-110, a.k.a electronic toy. Very good packaging, condition looked as on the eBay pictures. Serial number 400300. However, when I started playing with it I noticed that only the HAND CLAP had any volume. The other sounds were there, but very quiet.
I posted on the 99musik forum. I shortly got an answer from a guy that never had used a DR-110, but had taken a look at the schematics. He suspected the balance knob, according to the schematics all voices are wired through the balance knob except for the hand clap that goes directly to the amplifier.
ALL OTHER VOICES -> BALANCE KNOB -> AMPLIFIER
HAND CLAP -> AMPLIFIER
I opened the DR, and guess what, the soldering on the balance knob didn’t look at all like the other ones. Note that the schematics are seen from the top, my photo is from the bottom, that’s why the knobs don’t make sense at the first look.
I’ll have to fix this, to be continued…