silvertone roundie

[timmy]

the hv does not hold steady it will go from 24kv to 23kv so this is not steady. this is where the hv pot is at , max 24kv and if i lower it to 20kv it drops more with scene changes and tweaking the eff coil did nothing if anything i maybe got alittle as the hv probe needle moved up a speck when i lowered the ma to 190ma. i am about ready to air a nasty video of a silvertone in its last days,lol.

[DaveWM]

you are worried about a 1kv change? that's it? a total of 1kv? from dark to light? are you serious?

[ctc17]

How about C96 and C97? I have seen those go bad, they usually short.

A few kv or swing is not a problem and is normal.

When does it bloom?

[timmy]

no im not bothered by that but scene changes the hv drops from 24kv depending on the scene like white or others it will drop to 19kv. so its not regulating or something is dragging the hv down for whatever reason.

[ctc17]

Originally Posted by timmy

no im not bothered by that but scene changes the hv drops from 24kv depending on the scene like white or others it will drop to 19kv. so its not regulating or something is dragging the hv down for whatever reason.

I was talking to davewm and we agree if you are able to get the 1.5ma off the shunt, the hv is working ok.
Sounds like something is loading it down, overdriving the crt.

So if you get a commercial or something thats all white with text then the picture blows out and blooms??

[timmy]

if those 2 caps are off the lin pot then no they were not changed.

[timmy]

no it actually dont bloom from that its only bwhen i wanted to raise the crt bias to brighten it up alittle thats when it blooms and when white scenes are present the picture goes alittle dark because theres not enough hv it seems. if i leave the bias ccw i dont bloom but different colors make it dark and i confermed this by watching the hv probe on different scenes bias down.

[ctc17]

Maybe it had an esl dump.
Did you do the setup the way it says in sams under greyscale? Does that end up with the bias to high?
If you have a really strong crt the bias will be all the way down. You really only want to advance the bias once one of the screens is maxed out.

[timmy]

Originally Posted by ctc17

Maybe it had an esl dump.
Did you do the setup the way it says in sams under greyscale? Does that end up with the bias to high?
If you have a really strong crt the bias will be all the way down. You really only want to advance the bias once one of the screens is maxed out.

did the grey scale so many times now and it improves nothing. the thing with the drives,rgb i cannot get the rgb lines across the screen unless i raise the bias alittle then i put the service switch back to normal and then i have to lower the bias because its all bloomed. this is the only way to see the color line in the setup, nothing in the sams about bias at least that i remember. the strange thing is i can leave the rgb drives ccw and still have good color.

[ctc17]

Originally Posted by ;

If that jumper is missing, put it back as soon as possible to restore the regulation. If your HV goes too high, the CRT neck may shear off.

HAHAHA its not a 70s Zenith, its a silvertone roundie that can hardly produce 24kv when hit by lightning.

Originally Posted by timmy

did the grey scale so many times now and it improves nothing. the thing with the drives,rgb i cannot get the rgb lines across the screen unless i raise the bias alittle then i put the service switch back to normal and then i have to lower the bias because its all bloomed. this is the only way to see the color line in the setup, nothing in the sams about bias at least that i remember. the strange thing is i can leave the rgb drives ccw and still have good color.

Check the video output and voltages on the crt. I have a feeling something is being overdriven.

[Jeffhs]

[QUOTE=ctc17;3052349]HAHAHA its not a 70s Zenith, its a silvertone roundie that can hardly produce 24kv when hit by lightning.




I always thought that any color CRT installed in any make or vintage of TV (not just 1970s Zenith sets) could have its neck sheared off from excessive high voltage. Were Zenith TVs the only ones to have this problem under HV runaway conditions?

If there is no regulation of the second anode voltage on the CRT, the voltage will go sky high, of course, until one of two things happens: the flyback burns out or the neck shears off the tube. Another problem when the 2nd anode voltage runs wild is excessive X-ray emission from the front of the tube and elsewhere. This is why all CRT televisions, from about the mid-'70s until the end of the CRT TV era, were equipped by Federal law with HV shutdown systems that would either make the picture unwatchable (by throwing the horizontal oscillator far off frequency, so far that no amount of fiddling with the hold control would bring the picture back into sync) or by blanking the raster entirely.

[timmy]

maybe its time to just put it together and watch it the way it is rather then drive everyone including myself nuts. its been like this from day one and was told by don lindsly that something is loading it down and we were not able to figure it out yet. anyone want to buy a 63 silvertone,

[timmy]

the voltages were very close at the crt when i checked it yesterday. in a previous post i wrote what they were. i think page 3. sorry its on page 2.

[DaveWM]

try a new video out. a weak video out will result in a darker than normal pic.

[timmy]

Originally Posted by DaveWM

try a new video out. a weak video out will result in a darker than normal pic.

did that already to.