Make sure the pins are good on the crt. Lots of the cemented crt plugs loosen up and result in poor connections. If the filaments light in the crt, try lightly rocking the plug left and right to see if a picture flashes, if so, you need to resolder the pins of the crt, and also make sure you have good non corroded contact the crt socket. I run into this many times with the early 60s zenith b/w portables.
Funny you should mention that, the phenolic wafer board on the inside of the plug is toast! It's cracked and pieces are missing, but it is still functional. I'll verify all of the connections when I get the back back off, which will be later this morning if the kids behave
Should all that check ok, make sure you have good hv. If you have a probe, check to make sure you have HV in there, like around 20KV.
I do have a HV probe that I've never used.....the clip goes to chassis ground, correct?
That set probably has a 6GH8 h. osc. If you have a 6GH8 around, try subbing it to make sure. Those things are nothing but trouble. zenith sets are known for having corroded tube sockets even if the set is perfectly clean. What I normally do is shoot some contact cleaner into the pins of all the minature tubes sockets and work the tubes in and out. IF tubes in perticular are the worst, this will cause loss of sound and video resulting in just a blank raster.
I remember the 6GH8 discussion, this one checks out good, it was the first thing I thought of actually.
Just to note, that rappid "snapping" you hear is the vertical oscillator and is comming from the vertical output transformer. It changes the rate of the noise as you turn the vertical hold like you said. This is kind of a clue that your set will have vertical trouble once you get to see the raster!! Your picture will probably be rolling rapidly. Luckily Vertical problems are about the easiest TV fix.
I was pretty sure this was the case, but thanks for clarifying that
Thanks for the tips, let's see what damage I can do here
