Vintage Synth Repair

From: "fainardi83@... [vintagesynthrepair]" <vintagesynthrepair@yahoogroups.com>
To: vintagesynthrepair@yahoogroups.com
Sent: Monday, October 24, 2016 1:40:19 AM
Subject: [vintagesynthrepair] hohner string performer low volume on piano and violin










 


>all preset works except the lower piano and the upper violin
but i don't think it was the lm741 because is the lm741 was defect there was no sound upper and lower
for the piano i can hear a very very low sound of piano in the lower section, the same thing for the violin preset but in the upper section of the keyboard


any idea of the problem ? capacitor, diode, resistor
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Could still be the 741s, or any of those other components you mentioned, or something else entirely such as a cold solder joint or broken trace. No way to tell over the internet. If I had it here, I would need to follow the signal path with a scope or a signal tracer to find the point where it switches from normal volume to reduced volume. If I have a guitar amp or portable stereo  handy, sometimes I'll use that as the signal tracer . Occasionally all it takes for me is a close visual inspection.