First Post-Restoration Glitch

[roundscreen]

Just guessing, look for a electrolytic cap in the vertical circuit. IIRC It is a can cap. 40 uf @450 v or something close to that. Also check the vertical lin control. I have seen the lin control burn up before.
Good luck
Ed

[compucat]

I have had a chance to look into the vertical problem and it is indeed the vertical output transformer. One of the convergence secondaries appears to be shorted somewhere. When in the circuit, there is no vert. sweep, the two 2200 ohm resistors feeding 410V from the power supply start smoking and the transformer gets hot and emits an odor where this secondary winding connects. When I disconnect the winding, I have restored vertical sweep and everything is stable. I am going to replace the vertical transformer, the two power supply resistors and those 1000V caps as a preventative.

I think after this, it will be alright for a while.

[wa2ise]

Originally Posted by compucat

I have had a chance to look into the vertical problem and it is indeed the vertical output transformer. One of the convergence secondaries appears to be shorted somewhere. When in the circuit, there is no vert. sweep, the two 2200 ohm resistors feeding 410V from the power supply start smoking and the transformer gets hot and emits an odor where this secondary winding connects. When I disconnect the winding, I have restored vertical sweep and everything is stable. I am going to replace the vertical transformer, the two power supply resistors and those 1000V caps as a preventative.

I would think that the problem is that whatever the convergence secondaries drives has a short. Sounds like the vertical output transformer works fine when you disconnected that secondary. I'm thinking that the convergence secondary is part of the vertical output transformer, Yes?

[reeferman]

That 40 mike cap will cause the vertical to pull up from the bottom.
And to 3 gun color, thanks for saying vertical integrator in reply to my earlier answer. I couldn't think of it's name to save my life.

[compucat]

Woo Hoo - She's working again. The new vertical output transformer did it. Everything is back the way it was. I had to redo the static convergence as I bumped the crt neck components working on the set but after that, everything looks great again. I must have run the set for about six hours over the course of yesterday and no problems. In some ways I'm afraid to use it much in case something else goes. My wife seems to like the set but is skeptical that it will run for more than a month between repairs.

[compucat]

After more than a year of reliable performance the Zenith is having the same problems as before. I hoped the vertical output transformer I installed last year would last for years, it looks like I might have to replace it again. Any other Zenith roundie owners have this problem with repeated failures? I have not opened the set yet but the symptoms are exactly the same. So far all I have done to this set in the past year is touch up the greyscale. What is it about tube tv sets and vertical problems?