Background and History of this Amp
up to first repair attempt in 2015
Spec Sheet for Fender Dual Showman silver face Model AB763 (1968) [ Link ]
It was my Sophmore year in College; 1968 when I traded my two Fender Bandmasters and one Bassman amp for a brand new Fender Dual Showman. I was at the age where I still believed that bigger was better (the first amp I ever owned was a Fender Vibrolux - what I'd give to have that little amp today.)
I only had a band for a couple years after I bought that Showman and most of it's life -- since then -- has been putting to shame any stereo system I could afford. The last 20 years it has been pretty much idle, standing quietly in our rec room. Three years ago I began playing accoustic guitar and just last month I dusted off my old Guild Starfire 5 and plugged in the Fender.
It popped to life and the left "Normal" channel works but volume is not good (maybe 1/3). The right "Vibrato" channel doesn't work at all. All tubes light and there's no hum or noise. I played around a little and it sounded good but I was worried about running it like this so I turned it off.
I emailed a local repair shop and they said it would cost $75.00 to look at it and give me an estimate (which would be deducted from the repair cost if I had them fix it). They assured me that they could fix it but would not guarantee original equipment components. This seemed fair but then I though; "How hard could it be to fix a 'simple' amplifier? So I hit Google. What follows is log of the journey that followed. I write this for my own reference - the laying of breadcrumbs so that I can find my way back.