Late 1960s zenith color console question - Videokarma.org TV - Video

radotvguy · #1 07-23-2007, 10:33 AM

Hopefully someone can give me a me a little help .

I have a late 1960s zenith color console , which is a sams no #982 . 25 INCH RECTANGULAR . Anyhow i replaced a few electrolytics in this set which brought my picture and sound back . Then i had a problem with the picture was too snowy . So after cleaning the tuner and replacing tuner and IF tubes i seem to correct that problem . I had the set running for 30 mins or so yesterday and the horizontal starting acting up and would not hold . So i shut off the set, let it cool , then pulled the horizontal oss tube out which was a 6BA11, replaced it with a new one , then firied the set back up and got no picture at all , but also noticed the horizontal output tube was cherry red hot and brighter then normal . I shut it and thought maybe i did something but couldnt figure out what , so i put old 6ba11 tube back in and firied it up again , same issue , no picture , no high voltage and cherry red horizontal output tube . I am no expert but i think the flyback might be bad which is what is causing the horizontal output tube to glow so hot . Can anyone shed any light on this for me . The set was working. The damper,highvoltage regulator and rectifier tube are new .

jpdylon · #2 07-23-2007, 11:24 AM

despite the fact the tubes are "new" one may have developed a short. The red-plating condition you see is the HO tube drawing excessive current.

Its true that they fly may be bad, but strange that it happened all at once after working fine. Did you check the cathode current on the HO tube when you first got the set working? Was the fly running hot that you could tell?

I would go back underneath the chassis and check the components associated with the HO and damper tube. You may have a resistor that opened or cap that is leaky. Even film and ceramic caps go bad at time.

3Guncolor · #3 07-23-2007, 11:31 AM

I would check the horiz drive from the 6ball before even thinking the fly is bad. Zenith's almost never lose flybacks.

radotvguy · #4 07-23-2007, 11:52 AM

thanks guys , i will check caps and coponents in that circuit . The fly was not running hot before this .

drh4683 · #5 07-24-2007, 04:35 PM

Sounds like no horiz. drive. horizontal oscillator tube in a zenith color is a 6U10. 6BA11 is a sync/agc and vertical oscillator tube. What chassis the chassis number of your set? Check for about -58 volts on the grid of the horiontal output tube, 6LB6 (-DC meter reading from pin 5 to ground). If you have drive, check the damper circuit.

radotvguy · #6 07-26-2007, 06:05 AM

thanks Doug
I took another peek last night when i got home and i feel kinda stupid , but it looks like someone had the wrong tubes in the sockets . The horizontal ossillater should have been a 6u10 and someone had a 6ball in there and the vertical ossilator tube seems to be wrong to . I should have checked that from the beggining however i just assumed the correct tubes were in the set . Lesson learned i guess . Hopefully this goof up someone did , didnt damage anything else . I have a friend that is going to loan me a schematic on the set . Hopefully i get to this weekend . Thanks again Doug .