Rotary switch channels are acting funny

Discussion in 'Pickups & Electronics [BG]' started by CookieThe1th, Feb 17, 2020.

  1. CookieThe1th

    CookieThe1th

    Oct 4, 2019
    Greetings! I've had a 74-75 Gibson Ripper for a little over a year now, and it played and functioned perfectly until recently. The issue that I have now is that out of the 4 positions on the rotary switch, only one gives me "full volume". What I mean by that is that while positions 1, 2 and 4 work, they are appx. 25% as loud as position 3. Is this a common problem? I haven't been able to find anything that sounds similar to this issue using google or by searching on this website. I should also note that up until about November, each switch position gave me fairly even volume while switching channels.
     
  2. JTE

    JTE Gold Supporting Member

    Mar 12, 2008
    Central Illinois, USA
    I don't recall the switching of the Ripper, but I would suspect a short somewhere, or a problem with one of the pickups.
     
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  3. CookieThe1th

    CookieThe1th

    Oct 4, 2019
    Thank you! I have gone through the wiring and everything looks right. That's why I was thinking it was an issue with the switch. There is 1 setting where everything sounds great, but the other three sound like the amp is in another room
     
  4. JTE

    JTE Gold Supporting Member

    Mar 12, 2008
    Central Illinois, USA
    Which setting is good? The original wiring has position 2 as the "back" pickup only. The other three positions use both PUPs in various combinations. If the setting with the full volume is the bridge PUP only, I would suspect the neck PUP has a problem.
     
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  5. CookieThe1th

    CookieThe1th

    Oct 4, 2019
    As far as I can tell, the wiring and pots are all original. Given that, it's the 3rd position that works, which is both pups in phase and parallel. The other three, being (1)in phase/in series, (2)bridge only, and (4)out of phase in series are affected.
     
  6. 40Hz

    40Hz Supporting Member

    May 24, 2006
    home
    If all the wiring checks out and it’s not a dirty contact on the rotary switch that’s fixable with some residue free electronic contact cleaner spray, then there’s either an issue with the switch or a pickup.

    Check the resistance reading of the neck pickup. Both pickups should read close to 7.1K. If one isn’t, it’ll need a rewind or replacement. Fortunately Seymour Duncan can help you with both if necessary.

    If both pickups read correctly then the problem is with the switch.

    Quick questions: (1) is your Ripper mainly kept in a hardshell case? And (2) are you seeing any rust looking discoloration on the pole-piece screws or pickguard screws?
     
    Last edited: Feb 18, 2020
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  7. CookieThe1th

    CookieThe1th

    Oct 4, 2019
    It is kept in its hard case, and yes there is some rust on the pickguard screws.
     
  8. 40Hz

    40Hz Supporting Member

    May 24, 2006
    home
    You might be experiencing the nigh on infamous “gassing” issue with the pickguard. The plastic used in the early Rippers emits some nasty chemical vapors that can corrode the pickup windings and other electronics if the bass sits a lot in a closely confined space - like a hardshell case kept in storage - if it isn’t opened regularly and aired out.

    I’d definitely check the resistance reading of your neck pickup at this point. From the symptoms you’re describing you may have a shorted coil.

    Ed Friedland gets into that a bit in this video:

     
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  9. CookieThe1th

    CookieThe1th

    Oct 4, 2019
    Dang. Thank you!
     
  10. Peavaria

    Peavaria

    Oct 10, 2018
    Threads like this never cease to amaze me. Outstanding knowledge out there.
     
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