[Tomcomm]

Thanks for the replies regarding my warm up problem. I've been running silicon diodes in place of the seleniums from the first time I fired up the 55 and got only 390v of B++. Lost a lot of heat in the bargain. I replaced the rectifier’s 80uf big can electrolytic with a 100uf at 475v. The B++ goes to 455v at turn on and settles back to 410V operating. A Powerstat manually keeps the AC at 113vac resulting in a B++ of 410v which produces exactly +900v of boost and 30kv of ultor.

Since the boost voltage is used in the vertical oscillator height control, any change in boost voltage or the resistancs of the 2.5meg height control, both height and linearity greatly effects screen's appearance but more importantly vertical convergence accuracy! The height and linearity are both controlled with a cheap open terminal dual pot. The 5k linearity portion was open originally and I replaced it with a single pot mounted in a new control panel hole. When I hit the surviving height pot with Quick Freeze, it collapsed the vertical screen and destroyed vertical hold. As it dried out the screen circle almost returned to normal. I replaced it with a sealed military grade Allen Bradly 2.5meg pot I had from the ‘50s. When I adjusted it to the circle dots, linearity was restored and convergence improved significantly. Was this the fix? Time will tell when I fire the 55 tomorrow morning. All Hail Marys are welcomed.

I started using Quick Freeze on the rest of the vertical circuit resistors and caps but didn't finish yet since I was running my last can out. No further temp sensitivity so far. I took Bob’s suggestion and ordered five cans for the same $12 shipping as three, from Southern Hills. My nearest electronics store was a long trip and they wanted $8 a can. Santa Ynez is great to live in but major stores are at least 60 miles RT in any direction. ....Tom