Hi all,

I recently bought a Zenith 1955 console with Radio, Record Player and TV.
The model is R2337.
I recapped the radio, replaced output valves and made some small adjustments on the FI coils.
About the TV, it needs complete recap. The original horizontal valve (6CD6) has been replaceed with a 6DQ6 (making changes in the base pinout and adding a smaller upper cap to the fly-back) and it seems to work fine. I was surprised about that.
The thing is, I need to remove the CRT because I need to work on the base of the chassis.
Though as a hobby I've repaired many sets, this is the first time I have to work with a set with the CRT in the shassis and it looks pretty delicate.
In the front, at the bottom of the tube, there is a metal piece that prevents the tube to move further to the front and I can't unscrew it because the screws are below the CRT. This means, that I can't just slide the tube to the front after loosing the metal grip, I also have to lift it like one inch. I can't do this with the yoke assembly on so I guess I should unscrew it also.
If any of you is experienced on removing CRTs from Zenith 50's chassis, can you plese tell me the safest way to do it? I can analyze it and think of how to do it but maybe something will be missing and I don't want to risk the CRT (Here in Argentina it is impossible to get another one) and also I am afraid of my own health if the tube explodes somehow.
Maybe this is a silly question for most of you, but I prefer to ask in advance and not to have to regreti it. I really payed a lot for this set (here this stuff is almost unafordable because there are not too many) and I am also concerned about my own safety.
Thanks a lot in advance!!

This is a real pic of the set just as I got it:

I don't have here the CRT model but I think I made a mistake. It should be 21ALP4 maybe? It's a 70° CRT.

I don't have your exact chassis, but I've worked on a 1953 and a 1959 model (I believe that yours was made in between mine), and have enough experience to give advise.

First off make sure to remove the CRT and chassis together from the cabbinet. Any attempts to remove one from the cabinet without the other will fail and or cause severe damage to several parts.

Secondly one can work on the chassis with the CRT still attached. When I did mine I worked on a carpeted floor, and merely rollled the chassis with the CRT attached on its side and proped it up in a position that made recapping easy.

On both my sets the procedure for removing the CRT (once the chassis and CRT unit is out of the cabinet) is to loosten a screw that sets the tension on a metal band that straps the face of the CRT down to the chassis untill the band is VERY loose (loose enough to stick ones fingers between the band and CRT) you then make sure the socket and HV lead are unpluged and lift the CRT just over the metal piect that keeps the tube from being slid foreward and then slide the tube foreward and out of the chassis. The yoke should be affixed to the chassis and not to the CRT, and the CRT should be able to be moved easily with respect to the yoke (as was the case with mine) with the CRT only resting in the yoke like a cradle.

Hope this helps.

Good luck on your restoration!

Tom C.

Hi Tom, thanks a lot for your tips.
I still have one question, let me se if I understood correctly. The yoke is attached to the chassis. There is no connector, the cables get into the chassis so it will not come out with the tube. I need to unscrew the yoke from the chassis only to be able to lift the tube up, and then I should slide the tube towards me (if I'm holding it against my chest) letting the neck of the tube start like "coming out" of the yoke housing so the yoke will remain in the chassis (like flying, only attached with its cables)? the question is, the yoke, now as it is, is surrounding the neck of the tube without any attachmento to it?
thanks again!

One more question, sorry.
The tube is bigger than the chassis. If I rotate the whole thing, the contact surface to the rug will be 100% the tube. The chassis is very heavy, it will start generating uneven forces on the CRT. do you mean to rotate it 180° so the chassis will get horizontally positioned? Is this safe? If this is possible, I will not remove the CRT.
I've always wondered how you can manage to take measurements and make tests not being able to access the components on the chassis, so unless they used a special stand for it it should be possible to turn it around as you described.
Thanks a lot!

There are special, small test CRTs -- 8AXP4 or 5XP4 -- that can substitute for the big CRT when a chassis is on the workbench. You connect the little CRT with long extension cables, so then you can turn the chassis sideways, or whatever, with everything powered up.

That's how a repair shop could have worked in the old days. Not everyone has those substitute CRTs now, of course. Most of us make do some other way.

Phil Nelson

Get a block of wood such as a length or 2 by 4 that you can place along side of the chassis so that the set will rest both on the CRT and the chassis. If the power transformer is at one edge of the chassis and you rotate the set so that that side is down, a prop under the power transformer may be enough.

Thanks a lot Tom.
Knowing that this is possible, I will work on it this weekend and try to figure out how to do it safely.

I have a similar set, here is how I have mine set up to begin recapping. Now all I need to do is get started with it. Hope this helps.

Sorry for the slow response, I haven't been on in awhile.

The inside of the yoke is a slightly larger diameter than the neck of the CRT so there generally is enough wiggle room to angle the tube above the bracket safely, though one could loosen the yoke rotational adjustment and maybe other yoke mounting screws to make the yoke free to move much more with the CRT, but I've never felt the need to loosen the yoke on my sets when removing the CRT (ether way it can't hurt as long as you can put it back together).

When I pulled the CRTs on my sets (this is going by a memory that is over a year old) I grabbed diagonally opposite corners of the screen. lifted high enough to clear the bottom retainer without scratching the CRT, and pulled the CRT towards me untill the tube was completely out of the yoke. Then once the tube was far enough out of the set I tiped it and set it face down on the carpet.

My sets used electrostatic focus CRTs. If yours uses electromagnetic focus you may have to remove the focus magnet or alter the procedure to account for this.

My process for rotating the chassis may not have been the safest.....And if adding wood etc. to prop it up sounds like a better idea to you, then by all means add wood or whatever you believe will increase the safety. Zenith sets of this vintage here in the USA are not rare, valueable, or all that sought after so I was not so much concearned with safety of my previously mentioned sets as I just wanted to dig in to the restoration quickly, without much hastle. Considering that your set is more rare in your area and presumably more special to you then you should take as much time and care as you need to feel comfterable in preforming the restoration.

Tom C.

Great tips fellows!

I used this weekend to recap and repair the radio... A lot of work. Cleaning, also IF alignment, some tubes to replace, power supply resistors, and small modifications in the AC circuit. As I need to use a transformer from 220V (the voltage of our electric network) to 110V, I wired the on/off switch to the 220V side of the transformer so it won't be connected all the time while the set is not in use.
I will start working on the TV and post some pics.

Thanks a lot!