CTC-4 Director 21

[Electronic M]

Don't know if it would help, but I do have a spare CRT mount assembly out of something like a CTC-15 that I'd sell.

[SwizzyMan]

Sounds like too risky of an operation. Let's just get it going first i guess.

[SwizzyMan]

I replaced a shorted 12BH7 (R-Y G-Y Demod) and a shorted 6AG7 (Demod driver) tube hoping I would see at the least a bit of improvement. Well there was none whatsoever, if anything the picture quality has gotten worse by just sitting for a mere month. I still have no red which pisses me off since I really thought the shorted R-Y demodulator tube might have given me a hint of red when replaced. At one point I had red. Once I did a recap, I lost it which doesnt make any sense to me. Also I still need to figure out what all the interference associated with the color being present in the picture is all about. While I had the chassis on the bench testing voltages and checking wave forms, a resistor started smoking. It was a 10K 2watt resistor feeding a 285v supply off of the demodulator coil, its value has now risen out of tolerance so I will replace it regardless. Not sure if this may be an issue with the total absence of red. There is also a thick line on the side of the crt when the set it on, doesnt look like a drive line to me. Ive got my work cut out for me and I still have a lot to learn about these sets even though Ive restored two other roundies. Anyone here have any ideas on where i would even begin to look?

[DaveWM]

if it had red at some point before doing a recap, then you should check your work.

also, checking pin voltages is 1st (think you did this early on and there were issues with voltages at CRT pins)

if the Purity is way out, then getting good red will be an issue as well.

How does the CRT check for emissions and cut off?

[old_coot88]

It looks like the 3.58 oscillator isn't running.

[DaveWM]

good point about the osc, I am used to seeing the rainbows in the pic, but that is when its not synced up, could be not running at all. Get the scope and see if you can get a wave form from the color osc.

[SwizzyMan]

I am pretty sure the xtal is bad then. I mentioned earlier in this thread that it rattled when tapped on. Ill check for waveforms , but ill probably need a new crystal. Does anyone have one? Emissions are weird and somewhat weak at 6.3 but spring to life at about 7.5 volts. But ive known not to trust my crt tester sometimes. It tests good enough at 6.3 to at least produce some red.

[SwizzyMan]

I think Ive confirmed that the 3.58 oscillator is not running. I checked for waveforms on both sides of the crystal and I got nothing at all. Keep in mind I took this measurement with color control fully up, but not connected to the CRT so no HV or anything. I think I have a bad crystal.