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Thread: Hammond C2 Soft/Normal volume switch - soft not working?

  1. #1
    ppp Pianississmo SynthDan's Avatar
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    Hammond C2 Soft/Normal volume switch - soft not working?

    Hi friends,

    I've got a Hammond C2 that works and plays well, but when the Volume switch in the vibrato section is set to "Soft", no sound is produced. Everything plays fine in the "Normal" setting. I'm having trouble finding a schematic that shows what happens when the Soft setting is selected. The Soft/Normal setting doesn't seem to be part of the Scanner circuit, and I can't find anything on the Amplifier schematic either. Is there simply a resistor physically hooked up to the Soft switch that is bypassed when Normal is selected? Or is something else going on?

    Thanks!
    Dan

  2. #2
    fff Fortississimo geoelectro's Avatar
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    Look for C23. The switch shorts across that capacitor.

    Geo

  3. #3
    ppp Pianississmo SynthDan's Avatar
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    Hi,

    Quote Originally Posted by geoelectro View Post
    Look for C23. The switch shorts across that capacitor.
    So it turns out that, yes, C23 was shot and that was the problem -- thanks! The schematic calls for a 75 mF capacitor, and it doesn't appear to be polarized. I can't seem to locate an exact replacement, though I have been able to source an 80 mF non-polarized electrolytic capacitor, and a 100 mF non-polarized electrolytic capacitor. Can anyone confirm that these will be suitable replacements? And am I correct that C23 isn't polarized?

    Thanks!
    Dan
    Last edited by SynthDan; 10-11-2017 at 07:08 PM.

  4. #4
    fff Fortississimo geoelectro's Avatar
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    The cap is picofarad. PF .000075uf. This is a really small cap and non polarized. It doesn’t have to be exact. Probably anything between 50 ~ 100 pf will work. Varying the size will vary how much volume reduction you get.

    Geo

  5. #5
    ppp Pianississmo SynthDan's Avatar
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    Quote Originally Posted by geoelectro View Post
    The cap is picofarad. PF .000075uf. This is a really small cap and non polarized. It doesn’t have to be exact. Probably anything between 50 ~ 100 pf will work. Varying the size will vary how much volume reduction you get.
    Thanks Geo -- I didn't realize the schematic value (.000075) was in microFarads, and not Farads. I've got a 75 pF mica capacitor here already, I'll install it and test it. Thanks again for your help!

    Dan

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