1981 Magnavox with a problem.

[Jeffhs]

I agree with Sampson159 as to finding a schematic for anything you attempt to service or repair, be it a TV, radio or anything else electronic, before troubleshooting; "blind" attempts at finding trouble in a set often cause more problems than are solved.

My only other advice, however, is to be cautious around the CRT, as it has a very high voltage (in the double digit kilovolt range) -- the second anode voltage -- on it that can be lethal or can cause serious injury if you don't take the appropriate precautions. In color sets like your Maggie, the normal HV will be around 25kV or so; in a b&w set, it is a bit lower, around 18kV or thereabouts, but still, nothing to take lightly. And whatever you do, do not work on a TV or radio while the unit is still under power (plugged in to the AC line). Pull the plug and discharge the CRT in a TV before doing anything inside the cabinet. To discharge the tube, simply slide a metal screwdriver under the cap covering the high-voltage lead coming from the flyback. Remember that the HV charge on a CRT can remain on the tube for quite a while after the set is turned off, even if it has been unplugged and unused for years.