[Aperna1985]

Originally Posted by Zenith26kc20

I would look for a bad horizontal AFC diode. The selenium ones go leaky. Replace the two halves with 1N4148 diodes.
Also, check plate resistors on the 6GH8 for going up in value.

Originally Posted by old_coot88

If any set has weak horz lock and has an AFC dual diode, replace it out of hand.

I actually ordered one from Talon Electronics. It looks similar to the integrators you'd find in the vertical section on Zeniths except the schematic doesn't show a resistor.

Originally Posted by vortalexfan

Zenith didn't make their own tubes they usually sourced them from Sylvania and then had their name slapped onto the tube.

But I would guess that it probably is an original if not the second to original tube to the set (if the original owner of the set used Zenith Branded tubes as was suggested by Zenith back then on their TVs and radios.)

Was this the Zenith "Bugeye" TV? If so I had worked on one of these once and that was a pain in the butt TV to work on but when I got it going it worked really well.

With Horizontal or Vertical circuits the oscillator tubes need to be pretty much brand new (NOS) or else you're going to have oscillator stability issues in the vertical and horizontal sweep circuits because they are critical circuits.

I would definitely try getting some NOS tubes for the TV and try that out and see what that does with your TV.

It's actually a 1962 console TV but my next guess is that I need atleast a NOS tube in the horizontal. Funny part is the TV had a great picture when I started. It just had slight vertical collapse, after replacing the cap in the vertical the picture looked great for 10mins then the horizontal problem started.