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MuTron C200 Vol/Wah - DEAD "optos"

8/2/1999 6:43 PM
Sean McDaniel
MuTron C200 Vol/Wah - DEAD "optos"
I am a newbie on a quest to fix my MuTron C200 Vol/Wah.  
It was diagnosed by an electronic fixin' friend as having dead "optos". He said he would try to find some replacements.... That was a year+ ago. So I am on a quest to find the "optos" myself or build em from scratch.  
Does anyone know where I can find these parts? Or, does anyone know how I (the newbie) can build/repair the ones I already have? I got a schematic, but I need a little hand-holding. Thanks  
8/2/1999 9:40 PM
CJ Landry

I have the schematic for the vol/wah at the house and I will look it up tonight or real soon. The last time I worked on one of these the opto device, I think, is a phototransistor type. The LED portion is one one side of the blade mounted on the pedal and the other side is a phototransistor.  
I will look tonight and report back.  
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8/3/1999 5:25 AM

the pedal "expression" controls the current through the phototransistor(s)... the way you describe it CJ, it sounds like there a slit in the "blade" that is wide at one end and narrow at the other, mechanically varying light to the sensor... I imagine it would be simpler to vary the current through the diode to control LED brightness  
probably only one side is bad (the photodiode/transistor sensor) and maybe it's the only thing that needs to be replaced - LEDs are typically pretty robust
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