Sylvania 580 chassis (CTC-15 clone): Insufficient width.

[Gunslinger]

the Zenith HV regulation problems were traced to the VDR's in the circuit. If memory strikes me well, the replacement number was 63-9068 which were purple. The OEM's were blue.

[oldtvman]

Originally Posted by nasadowsk

It's a 580 chassis. The one right before the DO1. It's a clone of the CTC-15 as far as I can tell. I have the Sams for it anyway.

As for caps? I'm not replacing them all, just a few in the sweep sections. After all these years of getting wacked with high voltage pulses, I'd imagine a few are tired. What's interesting is the orange drop replacements are almost the exact size as the original brown caps. The 1.5meg resistors in the HV regulator circuit were both way off, which wasn't helping the HV adjustment. I have a matched pair in there now (which the Sams says they should be).

Right now, the big issues are:

* At 23.5 kv, the picture is fine until the brightness is turned a bit too high, then it loses focus and blooms. I'm not sure what's up with that (is it normal?). "too high" here means almost decent brightness - the CRT is a RCA Hi Lite replacement...

* The convergence sucks. I haven't even tried to do it, yet, though. That'll be the next battle - this set's historically been a bit bad in that department.

* Tuning in a color picture also tends to mean a bit of noise in the picture. Chroma alignment?

It's getting there, though.

The blooming problem is a result of bad regulation, try replacing the 6BK4 most times that will take care of the problem, if not look for problems in the B+ boost