sylvania tv lost video (have raster)

[Keefla]

Sylvania model ca8112wh
chassis ident number- e210002-1464351
mfgd- april '78 (<-figures....just hit 30)


a while back i posted about a sylvania TV i have, at the time it had some issues making noises and came to find out that the supposed 'repairman' actually did fix something (tripler). Ive been using it since then without incident till tonite. I was about to go to bed, i was watching Mythbusters when at the very end of the episode (closing credits) and video went out. at first i figured it was on the cable company's end but kinda thought it was awful clear blank raster (no static or anything) to be that. I got up and switched channel and it was still blank. I have sound, i have raster, just blank like the tuner is not workng. No magic smoke or any noises, just stopped displaying video.
Now be gentle, im a mechanic. i concider myself a decent mechanic but im still a just a mechanic, and while i enjoy electronics and the like ive never done much other then fixing a few old radios (recaps), and the regular stuff at work dealing with electrical issues (i work at a dealer so we see all the "bring it to a dealer" issues).
can you help? does anything commonly go bad on these to kill video? No matter what im not getting rid of it, just wanna save some money and get satisfaction out of trying to fix this myself. Any ideas would be appreciated.