Home › Forums › Help/Technical Questions › Ram’s Head — Sustain pot is a volume pot?

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  • December 2, 2009 at 3:53 am #79442
    devnulljp
    Participant

    What could turn the Sustain pot in an old ram’s head muff into a second volume pot? Bad caps? Bad pot? Something else?
    I picked up a later 70s BC239C ram’s head muff cheapish with a broken switch. Installed a 3PDT wired for TB and it worked but didn’t sound right and turning down the Sustain also drops the volume. None of my other ram’s heads do this, so I figure something is amiss. also, at maximum sustain it’s not really singing like a muff. Something’s not … engaged?
    So I opened up and repaired the old switch just in case it was my TB wiring, rewired it as it was originally, and the same thing. I figure some other component(s) is knackered. Any idea where to start looking. What could lead to the Sustain pot turning down the volume?

    Tone pot seems a bit off as well actually — with treble at both ends of travel and a bit muffled in the middle.

    EDIT: Just pulled the board and C1 looks to be newer than the others. It’s 10uF electrolytic marked SURGE
    Mine’s the same as this one. Which side should be negative on the C1 cap in this pic? Left or Right?

    IMG_2628.jpg
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    December 2, 2009 at 12:15 pm #104659
    The EH Man
    Moderator

    Replace all the electrolytic caps and see if that helps. When they leak voltage it’ll throw the other stages off.

    December 2, 2009 at 1:51 pm #104662
    devnulljp
    Participant

    Thanks Ron — quick check on orientation. In this pic, C1, C2 and C7 have -ve to the left,C6 has -ve to the right?
    C1 is 10uF, while C2, C7, and C6 are all 1uF…

    IMG_2556.jpg

    December 2, 2009 at 1:58 pm #104663
    The EH Man
    Moderator

    It’s hard to tell as it seems some of them are twisted around. Just mark the board before you remove them so you can be sure to put the new ones in correctly. I’d replace the 10uf first. That’s the style I’ve seen go bad more often.

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