77 sylvania

[Zenith26kc20]

Watch out for the vertical controls. I have replaced many of them for the problems you describe.

[DaveWM]

the little pots on the back of the pcb? should I try an test them in circuit?

I have cleaned the transistor sockets, and the serv switch.

[DaveWM]

I guess the smart thing to do would be to touch those pots when it acts up...

[DaveWM]

tried it again, vert is rock solid, before it was sort of like a mild foldover on the bottom, then some shrink from the bottom, and the occasional wink out to no vert at all.

I may reinstall that transistor to see if that really is the prob. I also have a transistor tester (checks beta with large meter readout) just to see if it test any different, that is if I confirm it is the problem.

[DaveWM]

Put it on the transistor analyzer (eico 685) could not get it to calibrate, squeezing the transistor and all of a sudden it would deflect full. Def a mechanical defect in the junction, so I will be tossing this one.

[DaveWM]

heat does the same thing, it would open and close based on holding a hear source to the transistor. I wanted to make sure it was not my alligator clips on the leads that were causing the issue (the good transistor did not have any issues with the leads).