mica capacitors

[Tom Albrecht]

Well, I would target resistors as the likely cause at this point. On the Sams schematic at ETF (not Bob's above - the numbering is different), I would check the following resistors:

R58, R59 - 2.2 meg
R61, R63 - 6.8 meg
R80, R81 - 2.7 meg
R82, R83 - 2.2 meg

In many of these sets, I find that some or all of the above have drifted to a larger value. Some of these can also affect the focus.

Also, you may have a whisker inside your vertical height control. Try removing it, cleaning up both the inside (remove the back cover) and outside of it, and reinstalling. Or sometimes something as simple as running a toothbrush between the chassis and the terminals of the control will do the trick (if the whiskers are between the chassis and terminals on the outside of the control). You might even be able to see evidence of whiskers by measuring resistances to chassis from the terminals (you may have to disconnect from the circuit to do so).

I presume you've swapped out both of the vertical tubes to make sure they are not the culprits.