After checking & finding loads of good connections, I looked at that tiny pot labeled R BKG (background) and wondered if it might be a tad funky. I rocked it back and forth a little and returned it to the original position. Looks like our red is back.
I'll play it on the bench for a while to make sure the cure sticks.
I would love to keep this guy going. The CRT seems a little slower to light up than when it was new, but otherwise it's a pleasure to watch. I pipe the audio to a KLH bookshelf speaker, so it sounds swell, too.
Thanks!
Phil Nelson