1967 Zenith table set with 25NC37 Chassis

[Olorin67]

Not a lot of the metal cabinet tabletops survived. I have a 23V metal cabinet set with remote. Mine might be a year or two newer...Still a bit buried in my storage locker.

[zeno]

I remember those. Still in the '68 catologue. One
remote & 2 others. I dont think they sold well
cause you could get a 20" Zenith & its almost
the same footprint. Also looks more normal with
all nobs on the right.

73 Zeno

[drh4683]

The 25NC37 indeed uses the 6BK4 and a 6C4 pincushion correction. It also has a 19EYP22 crt. That's also a flipper chassis as they put the HOT and the HV reg in that PITA spot behind the HV cage. Very similar to the more common '67 20X1C38 chassis except the 20X1C38 combined the PC correction into 1/2 of a 6KT8 which also serves as the color amp and the 6BK4 gets replaced by the 6HS5 pulse regulator. Same chassis footprint and general tube layout though.

Never did discover any documents with production figures for Zenith. I've had better luck acquiring leftovers from Motorola employees than I ever did with Zenith.

[dieseljeep]

Originally Posted by drh4683

The 25NC37 indeed uses the 6BK4 and a 6C4 pincushion correction. It also has a 19EYP22 crt. That's also a flipper chassis as they put the HOT and the HV reg in that PITA spot behind the HV cage. Very similar to the more common '67 20X1C38 chassis except the 20X1C38 combined the PC correction into 1/2 of a 6KT8 which also serves as the color amp and the 6BK4 gets replaced by the 6HS5 pulse regulator. Same chassis footprint and general tube layout though.

Never did discover any documents with production figures for Zenith. I've had better luck acquiring leftovers from Motorola employees than I ever did with Zenith.

The "N" line chassis had the metal shield that had to be removed to gain access to the high voltage rectifier. Also, the 6BK4 and the 6JS6 had the be removed to open the door. Lazy, sloppy technicians? bent the h*ll out of everything, instead of removing the shields.
The "N" chassis, 23V set had some kind of a crude looking adjustment device on the CRT neck, made of Masonite. Don't remember what it did. I was the only 23V Zenith that used it.

[captainmoody]

Doug has the answer to that.. I forgot what he said it was..

Oh, Dieseljeep.. I know what you are talking about. One of my techs used to BREAK off the tabs that held in the 9-160 modules, and throw away the red lock down. Ugh.. I hated that, and put an end to that crap as soon as I found out..

[drh4683]

Originally Posted by dieseljeep

The "N" chassis, 23V set had some kind of a crude looking adjustment device on the CRT neck, made of Masonite. Don't remember what it did. I was the only 23V Zenith that used it.

Ah, yes! Those were the big post-deflection purity rings! Zenith did it that way on the M and N line 23" sets. Very large and bulky apparatus and was secured with heavy copper braided cables that curved around the bell of the CRT. An unusual approach to purity adjustment. Not sure why Zenith did it that way in the beginning as I think the rest of the industry was using the much smaller and simpler purity ring assembly at the end of the tube.

[Electronic M]

Originally Posted by drh4683

Ah, yes! Those were the big post-deflection purity rings! Zenith did it that way on the M and N line 23" sets. Very large and bulky apparatus and was secured with heavy copper braided cables that curved around the bell of the CRT. An unusual approach to purity adjustment. Not sure why Zenith did it that way in the beginning as I think the rest of the industry was using the much smaller and simpler purity ring assembly at the end of the tube.

Perhaps they did that (assuming it was adjusted electrically) to try to put the purity adjustments on the front....Zenith seemed to like to make as many of the service adjustments front-adjustable as possible.

[dieseljeep]

Originally Posted by Electronic M

Perhaps they did that (assuming it was adjusted electrically) to try to put the purity adjustments on the front....Zenith seemed to like to make as many of the service adjustments front-adjustable as possible.

It was rear adjustable, with two large tabs, to move around.
If anyone remembers the Motorola ETS908 chassis, it had a dynamic blue lateral magnet, that was adjusted from the front, on the convergence board.
In the early days, they all had their quirks.

[dieseljeep]

Originally Posted by drh4683

Ah, yes! Those were the big post-deflection purity rings! Zenith did it that way on the M and N line 23" sets. Very large and bulky apparatus and was secured with heavy copper braided cables that curved around the bell of the CRT. An unusual approach to purity adjustment. Not sure why Zenith did it that way in the beginning as I think the rest of the industry was using the much smaller and simpler purity ring assembly at the end of the tube.

I thought it was for purity adjustment.
I didn't know, that there was an "M" chassis 23V rectangular set, just the "N" models.
I know, that RCA had a CTC17E chassis, that was their first 23V set. It had the same control panel as the CTC16E roundie. Most of them, didn't have that great of a picture and had purity problems.