[sdiy] SH-101 power supply

bill bigrig billbigrig at yahoo.com
Sun Jun 19 23:21:03 CEST 2011


 Forgot to mention, after pulling the transformer, TR-1 & TR-2 no longer get hot. I suppose I have either a transformer problem, or a direct short somewhere downstream. It appears that someone either fed this power with reverse polarity, (which D-8 seemed to take without problem), or fed it too much voltage. Oddly enough, where the schematic calls for a 100uf cap at C-4, this one has a 330uf. This must be an early unit. Between the R-8/L-1 difference and the input cap, other things have come up that do not match the schemo. Anyway, I can't do anymore diagnostics without a replacement for T-1. This unit came to me with a mod for a foot pedal jack for filter freq. and a jack to plug in a modulation pedal. I have removed  these and put those places back to match the schemo. The  synth has, "H F & P Sec." engraved on it. The e-bay seller said it worked with external CVs & gates, but it was DOA when I got it. I have a CPU, if needed. Thank you in advance.

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