Speaker selector stuck Fisher 500c

Discussion in 'Fisher' started by fahfisher500, Aug 2, 2018.

  1. fahfisher500

    fahfisher500 Active Member

    Messages:
    161
    Location:
    Huntsville, AL
    My A speakers are always on regardless of where the switch is positioned, even on headphone. I haven’t torn into it to clean it yet, but I thought I’d ask in case it is a known issue with a specific fix. All thoughts appreciated.
     

     

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  2. Catmanboo

    Catmanboo AK Subscriber Subscriber

    Messages:
    476
    Location:
    Atwater, ohio
    No such issue in either of mine. Have you verified that the switch parts are moving with the shaft when it's rotated? First thing I'd look at, mechanical function.
     
  3. fahfisher500

    fahfisher500 Active Member

    Messages:
    161
    Location:
    Huntsville, AL
    Not yet. It just happened tonight. This may seem like an incredibly basic question but how do you get the protective box that surrounds the speaker switch off? It appears to be held on by rivets do they need to be drilled out?
     
  4. Catmanboo

    Catmanboo AK Subscriber Subscriber

    Messages:
    476
    Location:
    Atwater, ohio
    It's got threaded studs, access underneath with nut driver. Nuttin' to it...
     
  5. fahfisher500

    fahfisher500 Active Member

    Messages:
    161
    Location:
    Huntsville, AL
    Thanks
     
  6. audmod01

    audmod01 Super Member

    Messages:
    1,206
    Location:
    Tioga, TX
    I have seen a number of rotary switches over the years that would develop a loose center rotating wafer which lets the wafer just stay in one position. I managed to repair the switches with some of the old flat style toothpicks and some glue. I wedged the toothpick between the shaft and the wafer until it took up the slack and provided a tight fit. I used some model airplane glue on the ones I did. Since there is no B+ on the speaker switch you do not have to worry about arcing. Put the switch in the position with the pointer on the knob showing Speakers A before securing the rotating wafer section to the shaft. Then check by rotating the switch to see that the other positions work correctly.

    Joe
     
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  7. fahfisher500

    fahfisher500 Active Member

    Messages:
    161
    Location:
    Huntsville, AL
    Ran into trouble. It looks like one of the connections holding the cover on is mounted to the frame behind the face plate, so I decided to remove the face plate first before disconnecting everything and removing the bottom cover. All the knobs pulled off easily except the bass control which appears to be glued to the pot post with some pretty strong glue. I can’t budge it no matter how hard I pull. I saw some knob pullers for guitar knobs on line, but I don’t think they will work, and will probably break the knob. I thought about buying a replacement knob online and pulling with pliers until it comes off or breaks, but I can’t find any for sale. Any thoughts about how to remove it short of destroying it?

    In the meantime I switched the #1 and #2 speakers so that my main speakers are now #1 and will always be on. This works, but I would like to fix it properly.
     
  8. rufleruf

    rufleruf AK Subscriber Subscriber

    Messages:
    1,025
    I'm sure I have a spare 500c speaker select switch - send me a pm if you want. The back cover for the speaker switch is held on by three spring clip type things - usually a little prying between the back of the faceplate and the cover will remove it without much fuss - pull top away from faceplate first, then the bottom out of the chassis.

    Re: knob. Pull the inner knob off first then the outer. If you really genuinely have to pry, get some blue masking tape and slide it under the knob on both sides as much as possible, and use two flat wide putty knives and try from either side - most important is only pry against the tape. If you beak a knob, they can be had. If you scratch the faceplate, it'll cost you.
     
  9. fahfisher500

    fahfisher500 Active Member

    Messages:
    161
    Location:
    Huntsville, AL
    Thanks Rufleruf, I was of the impression that there were nuts to be removed from an earlier posting. I’ll try to see if I can pop it loose as you describe.
     
    Last edited: Aug 8, 2018
  10. fahfisher500

    fahfisher500 Active Member

    Messages:
    161
    Location:
    Huntsville, AL
    Problem fixed! The cover popped off easily and it was very dusty underneath. I cleaned it with some compressed air, contact cleaner and silent slider (like fader lube) and it works perfectly. Thanks again Rufleruf, your advice was spot on!
     
    Last edited: Aug 8, 2018

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