Roland SH1000 repair help

Synth Repair
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1

roland sh1000 – no sound

Hey everyone! I’m having an issue with a Roland SH1000 synth. It turns on but it’s not making any sound. I can hear an extremely quite high pitched note when I press a key and crank my amp all the way up. I’ve checked the voltages in the supply and I’m getting the correct ones. I’ve noticed that when I trace the signal with a scope there’s a sine wave that I can trace all the way to the output jack, but the second I plug in a cable the sine wave disappears. I also noticed that when I try to listen to the sine wave with an audio tracer, the sine wave disappears when I clip the ground lead on. I’m pretty perplexed by this and any help would be appreciated, thank you!

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2

Hey!

Make sure your scope is grounded to an analog ground in the circuit, like ground side of an easily accessible resistor or cap. Sometimes chassis or other metal on a synth won’t provide a good enough ground (especially on older synths) so your scope input will act as an antenna and you’ll pick up the mains voltage as a 50 or 60 Hz sine wave on your scope. Be careful not to clip the scope ground to the side of a component that isn’t grounded because that creates a short circuit to ground that can damage the synth or scope.

If you’re still seeing a sine wave despite having the scope grounded then let me know.