whew.. lots to report
voltage regulation was not happening, I check the voltage at the grid and the cathode, should be 350/360 (-10v bias) was more like 375/300 or -75, so the shunt tube was completely cut off, not loading the fly at all, so no regulation. I checked everything there was to check but the VDR, no joy.
since there is no specs on the VDR I decide to just replace it. I found on that was suppose to be a cross, put it in, bingo regulation. I was able to get the grid voltage up to about 340 so a little low there, and I need to keep the HV set as low as it will go, that gets me to about 25kv.
I am going to check a couple more resistors and the boost voltage (yes replaced the focus diode that supplies the 900v boost that drives the regulation). I thought I checked them but will check again. I have another zenith set to compare to. there is a voltage divider in the fly cage that gets the focus voltage down from 5kv to the 900v so I will look there again. but at least its in the ball park now.
after I got it installed another problem popped up, color hum bars. Now it was fine before I pulled the chassis so I really doubt anything went bad.
after a few careful looks I found a rather large disc cap that seemed pushed down and possibly having a lead touch where it should not.
this is the only thing I really dont like about point to point wiring, esp with open bottom chassis. you have to be REAL careful about how you handle and transport the chassis.
anyway I moved the cap and the color hum bars are got, thank goodness.
I really like what zenith did on some of there 50's era tube sets, where there was a metal bottom plate. this not only shielded from EM radiaition, but prevented just this kind of problem, AND the chassi was much stiffer so less flexing and possible damage from that as well.
getting late so I will reinstall later in the week, but getting real close now.
Oh I also replaced some resistors that had gone out of spec on the chroma amp tube, that helped with the weak color (had to have the color turned all the way up).
Not too far to go
