Ouch! Poor, mistreated little Rumble!

From the looks of things you're lucky anything works at all, 'Cuda.
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dirk & John, I do believe you're right, the Rumble preamp/control boards are almost certainly bound to be proprietary and available only to
Authorized Fender Service Centers (AFSC).
'Cuda, you could always see what an AFSC would charge to clean and repair it for you. But, I'll actually be a bit surprised if you've even found suitable replacement switches for the Vintage button, but I sure hope you do! Please keep us informed of your progress.
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