1963 Zenith 16k27 chassis, BW, that my Dad bought new.

I'm slowly looking over things before i start on this, the 1st TV Ive done. I am far from being a pro, having only recapped a few radios with success.

Going thru the resistors, not lifting a leg but testing them attached, I have found 14 resistors out of spec. This TV has sat 40 years or more, but I'm wondering if that is way out of line as it seems like a lot of bad resistors?

I havent played with the tubes much but do have at least 3 bad, plus the caps to replace of course.

Are all the bad resistors a sign that there may be other serious problems and i should just forget this project and move onto something else? or is it somewhat normal? I keep reading how good these zeniths are so it seemed odd to me. I have 0 dollars into it so far, just my time. Thanks for you answers in advance.

Testing resistors in circuit is not reliable and you can get wildly incorrect readings depending on what other circuitry is attached to it. If you have reason to suspect particular resistors, pull a leg and then test. Otherwise I'd just stick to the caps and tubes and see where that gets you before concerning yourself with resistors. That said, I'm new to this hobby so perhaps others would give a different recommendation on how you should proceed. My suggestion is based on my background in 70's-90's arcade game and monitor repair.

Thanks for the response. I'll lift a couple either tomorrow or Thursday to see if they are the same.

IMHO start by bringing the set up slow before doing
any other work. Only do what you need to get some
kind of picture to be sure the CRT is still good.
After that you can recap a FEW at a time testing in between.
Start with electrolytics. Dont change disc caps unless cracked,
they rarely go bad.

Many resistors check bad in circuit, usually low unless an
electrolytic is involved. Keep in mind:
carbon resistors rarely go down in value much.
high values tend to go bad more often.
big wire wound resistors are either good or wide open.
ALWAYS use the same type to replace. ( or film for carbons).

Zeniths almost always come to life easily. They are the best
to learn on & are almost immortal. Good luck with her.

73 Zeno:smoke:

...carbon resistors rarely go down in value much.

Occasionally there is an exception to this, with 2 watt carbons in applications where they run exceptionally hot. The phenolic casing carbonizes, partially shorting out the resistive element inside.
An example is seen in certain Sylvania hybrid color chassis where both demodulator transistors have a 2 watt collector load resistor which chars progressively, eventially killing the transistor.

Occasionally there is an exception to this, with 2 watt carbons in applications where they run exceptionally hot. The phenolic casing carbonizes, partially shorting out the resistive element inside.
An example is seen in certain Sylvania hybrid color chassis where both demodulator transistors have a 2 watt collector load resistor which chars progressively, eventially killing the transistor.
That set is why I said "rarely" go down. I remember well doing
them with a lot of burned up stuff & transistors that had the top or
side blown off. GE C-1 chassis had an 8.2K 2W in the video
that went way down but had little effect. Probably others I dont
remember now.......

73 Zeno:smoke:

Thanks for the good advice all!

I lifted 3 of the ones mentioned. A 1.5M ohm that had tested at 14M tests over 20 lifted so is junk. Another that had tested way over before, after lifted, tests good. And the 3rd tests the same.

I'm going to follow most of the advice here. I do know it had quit working 40 some years ago so powering it likely wont work. So I will change the electro's, the one resistor and bad tubes and go from there.

It will be a very slow process but thats fine. i am not only trying to get it to work, but to learn a lot from it, as I have a lot to learn. Thanks again all!

Any resistor that reads HIGHER than marked value in-circuit is bad. Other parallel paths within the circuit can cause LOWER readings, but not higher.

If I find one that reads lower in-circuit, I look at the schematic to see if there are other components connected that can shift the readings. Non-electrolytic caps and tubes should not effect things (no DC path through them), but other resistors, inductors, and electrolytics (including power supply rails) certainly can.

As it turns out the resistor was a color coded capacitor, LOL. First one i have seen so lesson learned. Once I figured out the schematic it became obvious. I am hoping to recap it this week, and I have a isolation transformer coming in the mail to start it with.

my 2 cents.
do a base line run before recap, a 1963 zenith will have a good chance of working as is.

I generally monitor the line current and ramp up pretty fast if all looks good.
If its not a string series set you can pull the horz out tube out of the socket, and variac slowly IF its not been turned on in years. This will give the filter caps a chance to reform vs short out.

I generally will check the B+ resistance (set off) and look for about 8-12k, this points out hard shorts (like vertical out transformers).

I can't imagine any paper caps in a 63 zenith, so at most you may have to do the filter caps, prob an across the line bumble bee.

If I can add $.02 here: I have a Zenith ch. 15L37, a model year later, that I got from Kamakiri. I found a bad line circuit breaker, which I replaced. All 15 tubes tested good on my simple emission tester.

Then it worked after a slow power-up like Dave says. Then I replaced maybe 3 bumblebee caps and the rest of the paper caps were brown drops, not worth replacing unless you have an issue in that stage.

I disconnected in place and wired in all-new electrolytics, just in case and to keep it the bulletproof set that it is. Aside from cleaning all the controls including verticals, buzz and AGC, little else was needed.

Thanks for the advise and I am just reading it. Several e-caps were way off, over double high, and I replaced them all yesterday evening. The TV has been worked on a few times and has had a few regular caps replaced before as the soldering didnt lie.(e-caps were original cans) Several of the other caps were off 25-50% with one double. I had the caps already, so this morning I just replaced all of the tubulars but 1. The brown and red ones, some were ok and 2 werent. I replaced the bad ones. I had already tested the tubes a week ago with a tester I bought and had boughten replacement tubes and it needed 6. It does have a couple bad resistors I found while replacing caps but I will leave them for now.

I figured I was going to have to replace the e-caps sometime, and now I have one less worry.

worse case I can remove the parts I added. I didnt mind spending the few hours it took as I learn from doing, as they say.

Now I am just waiting for my isolation transformer to arrive! It is kind of a variac too, its an isotap WP-27a. The TV is sitting on its original stand waiting.

Can I still test it for shorts as mentioned and do I remove the horiz out tube to do that part? Different paragraphs so I'm not sure. And if its 8-12K, then that means it has a short? or is good?

I do really appreciate the advise and support. Thank you

find the output from the B+ check resistance at that point to ground. will start low and as filter caps charge up from meter, eventually should settle down around 8-12k. do this with all the tubes in.

on the power up, I generally pull the horz out tube and the vert out tube, the reason being at low voltages there could be a lack of drive causing too much current to be drawn. This is largely just a guess on my part, but the assumption is the set was not designed to be run at low power, so by pulling the tubes that have the most power thru them, there should not be a problem.