HV divider question for old Zenith techs.

[Electronic M]

I have a 1971 Chroma color Hybrid that I purchased from DRH4683 several years back.
It has been having focus isues for most of the time I've owned it. The issues began with the focus lead arcing to a grounded strut it was touching. When I spotted the problem (it was the first case of arcing I ever needed to fix) I wrapped the arc point with several layers of electrical tape and that fixed the problem for a long time. I might add that I used the set as a daily driver for between a week and a month not realizing that the noise was arcing before repairing it.

This repair held for a long time before the focus got squirily again this time it was really bad, and I was busy for a long time and ran the set with bad focus (that would improve after around 30 minutes of operation) for over a month before getting to fixing it. The tape had gotten brittle and crispy so that time around I decided to use a strand of plastic fishing line tied to a strut a couple of inches away to pull the line away from anything it could arc to. This repair has been sucess full, but the focus has gradually been getting worse I added an aditional 4.7m ohm resistor in series with the one in the HV cage and was able to get razor sharp focus with the control maxed out.

Reciently the focus got bad again and I added a 6.8m resistor (this was during the reassenmling of the set after a cateracting) During the adding of that resistor I dripped a solder blob on to an above chassis terminal and shorted all but the 400V and up B+ lines. Amazingly the HV still worked despite the H osc. having no B+. After much trouble shooting of the horiz, section I realized what I did, cleared the B+ short and replaced a power resistor that the short had fried.

Afterwards the width was greatly reduced even with the "increase width" jumper in place it just barely fills the mask, but the focus was razor sharp.

That was a few months ago.... More reciently the focus has gotten lousy and does not come back in nomater how long I run it. I stopped using it in the last few days as there is now fairly loud arcing comeing form somewhere.

I'm planning to take this console out of the stack I have it in, and trouble shoot it soon, and I've been woried that my doubler is going bad, and if fixing the arcing don't help and my HV is right I will want to replace the doubler as process of elimination will leave it as the prime/only suspect. I have a spare Zenith doubler (pictured Below), But I don't know what part # my original is so I'm not sure if the spare is right or not.



According to the schematic the doubler in the set contains a 40m ohm resistor between the HV lead and focus lead, and a 200m ohm between the focus lead and the ground(it goes to ground through the 15m ohm focus pot in series with that afore mentioned 4.7m ohm resistor that I've been adding aditional resistors in series with) This is by memory so if I'm wrong or hard to understand I can post part of the schematic to clarify.

If you can offer further insight in to this trouble or preferably know what the internal wireing of my replacement is, Please feel free to chime in.