Originally Posted by Beerstalker
Any ideas on what the problem might be, and how I might be able to fix it? I'm pretty good with tools, but if it comes down to soldering I'd probably have someone else do it (my hands are too shaky).
I would start, unit off and unplugged, at the red CRT socket bd and see if any of the conn's on it have gone cold solder visually. You don't have to remove the bd, just unplug it from the CRT prongs and check it out, fully wired up. Be careful, there will still be some live voltages on it, even tho unplugged from the wall.
If not I would put it back on the CRT prongs, turn the unit on, and very carefully wiggle the board by its edge, to see if you can make the red come and go.
Touch JUST the edge. Don't EVER go in to live circuitry with an open hand. Even if you are going to touch something that might be live, touch with the BACKS of your fingers, not the fronts, where HV might cause you to clench, thus sealing your fate. If HV hits the backs of your fingers and you clench, at least you clench AWAY from the circuitry.
As such, this is best left to a qualified, experienced service tech, used to HV and who knows how to handle it, as further searching for the problem has to be done on LIVE circuitry, while watching for the problem to get triggered, one way or the other.
If your soldering skills are adequate, completely resoldering the red CRT socket bd might do the trick. Unit unplugged from the wall, of course.
Or the bad conn might be elsewhere in the unit, requiring poking around in there at other boards with a NON conductive poking device, but with the unit ON, which might be hazardous to your health.
Since you got it free, you might want to invest in a repair from your local qualified service repair tech's services on this one. There are literally dozens of places in the unit where the red chain of events could be losing its connection.
On the bright side, when it works it works fine. This is not an awe-inspiring, stump the technician kind of problem!
It's simply a make or break of a connection, somewhere in there.