Randall RG80ES - help troubleshooting dead red channel?

[lossfizzle]

Thanks very much for the n00b-friendly response, DrGonz. Particularly like the continuity check advice. Believe me, I do err ridiculously on the side of caution - perhaps too much so (thus, 15 years of DIY DC electronics messing about and still no meaningful live-mains-circuit experience). I hopefully will bring back some readings on this bad boy later today.

[JHow]

This looks very similar to my RG80/100ES.  To the poster that questioned the "double-pot" I think that is the push-pull switch for the diode-clipping on the treble switch?  Mine has that feature.  When I got it it had some issues.  It still has some hum, but I think that is a "feature" too, to some extent.