1966? Zenith Color Tube TV

[Lain94]

Originally Posted by zeno

Coils
You can rewind coils onto another form. All Zenith conv
panels through the hybrids used them. Swap the slug too !
Panels have a S-##### number that may have a sub. I can look those
up.

Rejuve
Kicks the can down the street. Gives the cust time to save up
the $600 +, a LOT of $$$ back then. Using a modern B&K
or Sencore is best on clean & balance. Heavier settings are
last ditch. Results seem best when you get lots of needle swinging
& flashing in neck. Unpredictable but can stretch things a few
years at times.

Zeno

From what I read online the filaments of the older CRTs from the 60s and prior tended to be thicker and more rugged due to the filament being thorium based. I definitely saw quite a bit of sparking and flashing when doing the rejuvination at the time. It was a situation where I had nothing to lose because this CRT clearly had been used ALOT and the chassis's dirtiness testified to this. I always wonder if there would be any money in rebuilding old CRTs again, i mean if someone got into that business they would be the only one in the whole world doing it.

[Lain94]

Also, I realized this tv chassis has a "stick" style shaped recitifer diode known as GECR-1. These apparantly are known for failing thus I will be replacing it as well while I am at it.

[Lain94]

Also question regarding L 40 and L 42 adjustable inductors on the dynamic convergence plate on back of tv. The sam's photofact schematic does not show dots for the inductors but instead three horizontal lines with a downward diagonal line arrow one the right of each of those inductors. What direction are they supposed to go? The NOS replacements I got are not as obvious as the original zenith branded oem ones. From what I understand inductors do not have polarity per say but can influence polarity?

[Lain94]

https://imgur.com/a/geG4j6l

[Alex KL-1]

Originally Posted by Lain94

Also question regarding L 40 and L 42 adjustable inductors on the dynamic convergence plate on back of tv. The sam's photofact schematic does not show dots for the inductors but instead three horizontal lines with a downward diagonal line arrow one the right of each of those inductors. What direction are they supposed to go? The NOS replacements I got are not as obvious as the original zenith branded oem ones. From what I understand inductors do not have polarity per say but can influence polarity?

For one coil inductors, really don't made a difference in adjusting (results/value depends only about the slug position), unless if have a PM like linearity control, but makers for sure padronize positions/connections, to facilitate assembling and helping QC.
EDIT: in some secial cases, with crammed circuits and coils very close, is good to follow the original position, due to cross coupling/leaking magnetic fields, but I'm pretty sure that in a normal TV this cannot be a issue for these circuits.

[Lain94]

That is good to know. I was worried about this being an issue. Either way I will be prepared and will be testing the tv not too far off from now. Zenith tvs of this era had a pretty good reputation for reliability

[Lain94]

Update: I have decided to remove the old flyback as it looked quite dirty and the rubber tire was hard as a brick due to high hour use and may have had arcing issues before. Cracks are visible as well. Will keep it for future repair. I am going to install a NOS Thordarson flyback for this tv like I did for my Ford Philco tv already. I might as well since I want to make sure this tv will be in top shape for many more decades of use and service.

Does anyone know what modern common diodes I can use to replace a GECR-1 stick rectifier diode?

[zeno]

Focus rects were usually on the replacement along with other stuff.
We always used the Zenith replacements.
The rect is common & was sold by ECG, SK, GE etc...
Google it.

Zeno.

[Electronic M]

It's kinda wasteful to replace a good working flyback because it doesn't look good. There's not a limitless supply out there.

I've seen mint looking flybacks be dead and I've ran destroyed looking flybacks for years.... Electricity doesn't care what the path looks like as long as the path functions.

Flybacks and HV cups clean up nicely with off the shelf rubbing alcohol, and tougher dirt can be removed with spot treatments of Goof Off....Heck severe carbon tracking can often be permanently cured by Dremeling out the carbonized bit of insulation and replacing it with silicone caulk.

[Yamamaya42]

Originally Posted by Electronic M

It's kinda wasteful to replace a good working flyback because it doesn't look good. There's not a limitless supply out there.

I've seen mint looking flybacks be dead and I've ran destroyed looking flybacks for years.... Electricity doesn't care what the path looks like as long as the path functions.

Flybacks and HV cups clean up nicely with off the shelf rubbing alcohol, and tougher dirt can be removed with spot treatments of Goof Off....Heck severe carbon tracking can often be permanently cured by Dremeling out the carbonized bit of insulation and replacing it with silicone caulk.

agreed, very wasteful

a bit of corona dope works wonders

before.
http://suzaku.live-evil.org/0716221404.jpg

http://suzaku.live-evil.org/0719221857.jpg
after.

from my hoffman colorcaster television
working fine for over a year now,

[Lain94]

Originally Posted by Electronic M

It's kinda wasteful to replace a good working flyback because it doesn't look good. There's not a limitless supply out there.

I've seen mint looking flybacks be dead and I've ran destroyed looking flybacks for years.... Electricity doesn't care what the path looks like as long as the path functions.

Flybacks and HV cups clean up nicely with off the shelf rubbing alcohol, and tougher dirt can be removed with spot treatments of Goof Off....Heck severe carbon tracking can often be permanently cured by Dremeling out the carbonized bit of insulation and replacing it with silicone caulk.

I forgot to mention I am keeping the old flyback for repair and cleaning just like I am doing with the old ford philco flyback. Either way I had to remove them and figured that since I did I might as well put the new ones in each to save time and rule out the flybacks when diagnosing the current issues. I definitely have no desire to throw out the old flybacks though. I am pretty confident I can seal them out with electronic grade silicone among other little things to help fix any arcing they themselves may have.

[Electronic M]

It's better to not change them if they aren't genuinely beyond reasonable repair. There's fine wires and terminals you can break, leads you can get mixed up, etc. Also better than 90% of flybacks have plenty good access for cleaning while installed in the set once the HV cage is dismantled from around them.
Heck, unless I can hear arcing or corona I typically don't bother cleaning, and when I do hear it sometimes very little actually needs to be cleaned to stop it.

When it comes to original transformers unless they smoke they should be left installed.

[Yamamaya42]

Or in more direct terms...

https://encrypted-tbn0.gstatic.com/i...Optnw&usqp=CAU

[Lain94]

The tv is nearing its first test, TV is mostly reassembled now but a few issues. One is concerning the CRT tube pins, they are bent because when I got this tv the plastic guide piece that normally is at the end of the neck holding the pins straight is broken and most of all of the plastic piece is long gone.

CRT tube socket that plugs into it has one of the wires pulled out and the end of it is a metal clip like connector thing. Basically looks like a lead. How do I put that back into the CRT tube socket? Can I solder it back into the CRT tube socket?

Also as happened with the Ford Philco tv, the zenith tv's CRT anode metal clip broke off the wire due to metal fatigue and corrosion.

Next realization I made was that out of the three IF tubes. The first two should be 6EH7s which they are....but the third IF stage tube should be 6EJ7 according to the photofact, parts list, and schematic but the tube in that socket was also a 6EH7...? Not sure if this was done in the factory or by a repairman or the prior owner at some point. From what I can understand a 6EH7 is inferior to 6EJ7 in terms of what it can handle performance wise despite having the same filament voltage and pinout of course. Either the photofact is wrong, the factory goofed up (I doubt it), or someone replaced it with the wrong tube?

Anyways getting all the wires plugged back in was surprisingly easy despite how many wires there are. The chassis and tuner often labeled what went where plus I took a ton of photos early on.

What is surprising to me though is how there are barely any cataracts on the crt TV at all....despite the TV showing all the signs of high hour use.

[zeno]

1st & 2nd IF are 6EH7 third is 6EJ7. Only tubes to beware of on
some chassii are the damper & HV reg. Must be the right pair. See tube chart or label on the HV box.
Replace CRT key with any. be real careful bending the pins ! If rot is on
focus pin watch for too much focus V. Sockets can be drilled apart
or replaced with near anything. DO NOT solder to CRT pins !!!!

FBT's when new were an off white color. Every one I remember that was
bad had turned yellow & brown, sometimes with swelling or cracks. They can look real bad but still work fine.

Zeno