A Confession

[miniman82]

Originally Posted by Hagstar

Well it can be adjusted up to 22.5 kV, control works but adjusts exactly as before with flyback working- 21-22.5 kV. By stuck though I'm more referring to the way all reports I've seen say other CTC4 owners get this same slightly low max high voltage. It's true I haven't unhooked shunt tube to check that system- will do so.

You're not talking about mine then, all my early color sets make an easy 25kv. More if you aren't careful... Only sets I was never able to get more out of are the CTC-5's of course (my Wingate tops out at 22.5 no matter what I do), and some of the other RCA's like the 7's and 9's. Some of their later sets had better HV production, but those used compactron output tubes not octals.22/22.5kv isn't bad though, as long as it isn't sagging or blooming on high brightness scenes you'll be OK. Voltage is only one piece of the pie, have to have the current as well or it won't perform.

On the shunt regulator adjustment, you should be able to pull a full 1ma on the shunt tube's cathode with brightness all the way down. If it's higher than that straight off the bat, you may have to play with the grid circuit resistance to get it in spec. Not at all uncommon, the Silvertone I'm working on right now had a badly drifted 6BK4 grid resistor that caused hv to sag all the way down to 8kv. Changed out that resistor, boom got a full 24kv without breaking a sweat.