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Thread: 1983 Fender Showman Channel Switching Issue

  1. #1
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    Feb 2021
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    1983 Fender Showman Channel Switching Issue

    Hi,

    I have a 1983 Fender Showman, a solid-state amp from the Rivera era, and it has an interesting problem.





    On the front panel, Channel 1 works great. However, I cannot switch to channel 2.

    So I tried plugging in the footswitch to see if it was a bad switch on the front panel, and this is where it gets interesting. When I plug in the footswitch and hold down the Reverb button, I CAN switch channels, and play thru it with all channel 2 controls working, but only as long as I hold the Reverb footswitch down. As soon as I let it go, nothing.

    So the switches themselves appear to work but somewhere there is a problem. The only thing i have done so far is to replace the input jack with a generic alternate- I'm not sure if that would affect channel switching or not.

    I'm attaching link to a PDF of the schematic- if anyone can help me trace the signal path and recommend some possible solutions that would be greatly appreciated!

    https://drive.google.com/file/d/1N5O...ew?usp=sharing

    So far I have tested IC's 1 (the schematic seems to indicate this is involved with channel switching) with a multimeter in diode mode. I don't know if this is useful info or not, or if a o-scope is needed.


    Here is IC 1 and the values I got:



    Hopefully someone can give me an inspiration or two on this. Thanks in advance!
    Last edited by DJ5D; 02-12-2021 at 05:10 PM.

  2. #2
    Forum Member Offshore Angler's Avatar
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    Re: 1983 Fender Showman Channel Switching Issue

    First thing I would do is put the meter on the switch and make sure it's functioning.
    "No harmonic knowledge, no sense of time, a ghastly tone, unskilled vibrato, and so on. Chuck is one of the worst guitar players I know" -Gravity Jim

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