View Full Version : Advice on a 1951 Zenith combo console


PaulOF
11-05-2006, 03:58 PM
Good people,
I am new to this list, and am looking for some advice.
I am starting to restore a 1951 Zenith tv/am/fm/phono console
(radio chassis 8H20, cobramatic s-14029, tv chassis 24H21).
I've been working with old radios forever, but the only TV I ever restored
was a Hallicrafters T-54 that I did in the mid 70's. (It amazes me to realize
that the set is now twice as old as it was when I restored it. It was my
dad's and I remember sitting on his lap watching horseraces on it when I was
around 3 years old, but I am wandering off topic.)

Anyway, I expect few problems with the radio/phono stuff (except finding a new cartridge for the cobra-matic) but every time I look at that huge 19" picture tube I feel daunted. That sucker is almost as old as I am and I doubt it has the kind of implosion protection that more modern CRT's rejoice in. What sort of precautions should I be using when I handle it? I assume that I will have to somehow remove the bezel from the console and take the tube out the front before I remove the chassis from the set? Eye protection seems obvious. What about body armour? What is the safest way to store it while I work on the chassis? I am trying to track down a small "test CRT" to use on the bench while troubleshooting. Any suggestions or advice you might have would be appreciated.

I am just starting to recap the receiver, but I would like soon to get the TV chassis out of the console so I can let someone else get started on restoring the wood.

Thank you for your help.
Paul

Chad Hauris
11-05-2006, 04:31 PM
It seems like on a lot of these old Zeniths the crt is mounted to the chassis so the whole thing comes out of the cabinet by removing the bolts under the chassis. I would just lay the chassis/CRT unit on its side carefully when I would work on these chassis.
There is usually a strap around the front edge of the CRT that holds the front to the chassis and a bracket in the yoke area to support the neck.
The CRT usually never comes out the front. Look around the edges of the CRT and you can see if it is mounted to the cabinet or the chassis.

nasadowsk
11-05-2006, 04:47 PM
Is it a glass or metal tube? I recall Zenith used metals for a whle (it was an industry fad).

Some sets, the tube is attached to the chassis, others, it's attached to the cabinet. Some sets you pull the tube first, others you don't. Got pictures of thise thing?

If it's a mteal tube - they're pretty sedate, but they can zap you :)

Glass ones, no, they don't have modern implosion protection. But, the normal handling precautions apply - don't stress the neck, wear goggles, use gloves, don't scratch or hit the thing.

You want creepy, 21" color tube :)

USE YOUR HEAD!!!! By far the best advice - if it seems like a bad idea, it probbably is.

Storage - In a box, put old towels on the bottom, lay it face down, make sure the edges are supported. Don't let anything fall on top of it ;)

Remember that some sets can build/hold a static charge, even long after they're turned off. Ground the HV cup (always), and watch it when you pull the tube - avoid the contact.

Not a bad idea to clean the thing off while it's out of there - it looks nicer clean, and dirt creates HV leakage paths. I use Windex, and if I'm desperate, a really gentle brillo+water can get tough spots. You might have an aquadag coating on the outside, esp if it's a newer tube. Those like to flake off or rub off sometimes.

Metal tubes are easy to handle, they don't really implode, but they ARE delicate! And hard to find.

When I redo a TV, I like to make sure the HV box is as clean as it can get, and it's not such a bad idea to replace the HV lead from the 1B3 to the CRT, the old one might be leaky.

Remember once the HV box comes alive, that you've got HV in the sweep circuits. The bulk goes away when you turn the set off but the CRT and Horz output area can still pack apunch. Use a discharging wire. That little 'pop' gets to be relieving after a while :)

Test CRTs show up on ebay from time to ime, and someone here might have one. And HV probe's not a bad thing either, though not needed for B&W. You WILL need one for color. I never used a test CRT but they look useful and fun.

Oh, you're gonna have fun with the ion trap adjustments :) Don't panic the first time if no picture shows up - carefully adjust the trap and yoke.

bgadow
11-06-2006, 12:00 PM
Those Zeniths are kinda overbuilt; lots of capacitors to change, more than some other brands. The one I did had an unusual number of bad resistors.

If you don't feel comfortable with that crt on your bench, go with a test crt. They don't usually sell too high. I have a Sel-son remote crt which is real handy.

I have an Andrea this same age with a chassis mounted 16" metal crt. Not really that big a deal. Just take your time and pay attention every time you move that chassis.

PaulOF
11-07-2006, 09:28 AM
Thank you all for your advice. I'll keep you posted as I make
progress.
Paul