I carefully rotated the ion trap and it came off snug but easily. The CRT is now in a box but I'll be putting it in a safe place tonight.

I flipped the chassis over and had a closer look. The good news is the guy who added the electrolytics just tapped them into the existing and ran them parallel. I can just snip them out and restuff the originals.

I'm guessing the flyback comes out by undoing the two bolts at the top of the pic. I'll go try to get some shots of it.

The flyback doesn't look like a happy camper. Is this something that can be tested easily or is a replacement inexpensive enough to avoid hassle?

This one would be a lot better Is there a technical reason the original has all that goo surrounding it?

No doubt in my mind now. That flyback is another fire waiting to happen. It's already been on fire once.
Look at the distorted donut, the charred insulation, and, the big drips of wax.
This bad boy was a flaming mess.
The good news is if those flys are the correct numbers, this set can be brought back to life again.
I suspect the horizontal output was drawing too much current, which can prematurely ruine the flyback.
Trying set after replacement, rebuild needs to be done carefully..
Current draw on horizontal output is crittical..

I once had this model, sadly, in this good shape. Also had a dud pix tube, and, its' fly had also been on fire. Flyback tester proved it to be shorted.
I was told at the time I'd never get the flyback. I threw out the set.
That was 30 years ago..
I love the style.
Oh. That metal tube is 12UP4. Mine had the same tube.
12LP4 is an all glass tube.
Bill Cahill

Thanks Bill. I plan on taking my time and doing this right. I need advise on the resistors. Should all of them be replaced regardless of their condition? It seems like every thread on TVs I've read someone has to go back in and replace open resistors.

Too bad you got rid of your porthole

Any ideas on where I can find a flyback for this?

If you have the schematic then I'd use an ohm meeter to check for continuity of the windings. If any are open and the break is not in the leads going in to the fly, then it is bad, but if you have continuity I'd try to restore the set and see what happens. There are not many spares around so if the original, no matter how ugly it is, can still function properly I'd stick with the original in your shoes.

Just my .02$

Tom C.

I can't quite tell is the flyback is just very dirty or if it is strangely melted. Try gently brushing it with a paint brush and see if it will clean up.

It's very melted. I guess it wouldn't hurt testing it and seeing if it can be resurrected. What is the reason these were coated in rubber?

Old flybacks were coated in wax or rubbery stuff to prevent corona, arcing, potential meltdown.

I would clean it up, test as recommended, and see if it works after you recap the TV. Flybacks are not cheap or easy to find, for the most part. I have seen flybacks that lost a lot of wax yet still worked normally. You have nothing to lose by trying, and it would be a shame to throw away a usable fly just because it's ugly. If this one works, you can recoat it.

Regarding resistors, I usually recap a set, carefully bring it up, and see how it works. If a resistor is broken in half or obviously burned to cinders, that should be replaced on the first go-round, but shotgunning every resistor for no good reason is invasive and unnecessary.

If the TV misbehaves after recapping, then you would naturally check resistors along with other components in the misbehaving circuit. Most resistors were originally manufactured within +-20% tolerance, and in some applications a resistor can be more than 20% off spec without degrading performance. When they change value (a function of aging), it's usually by drifting upward. Where the manufacturer needed greater precision -- say, 5% or 10% tolerance -- that's normally indicated in the schematic, and of course significant drifting in those might cause problems.

Regards,

Phil Nelson

Look at the winding. It's charred. Look at the board. It's burned. Look at bottom of rectifier socket. How ya gonna clean that up?
Ohm meters won't do any good. You need a flyback tester.
In my opinion, if there isn't an exact flyback replacement availlable, set would have to be re wired for another type of flyback, yoke, and, linearity coil. No insult intended, but, a newby would be hard pressed for such an undertaking.
In my opinion, you might be better off putting it back together, selling it to another collector with more experience, and, get your experience started with eqsier sets such as Admiral, Bendix, and, Muntz.
Zenith, and, Philco predictas aretwo, of three of the worst nightmares anyone could take on. The third are the GE series string sets, including the Locomotive style sets. Dumont made a good set, but, there is alot to the early ones, and, you'd be starting kind of early on a more difficult set. Start out simple. Get an Admiral.
I've had good luck with those.
Not a real hard set, yet, educational.
Read my thread on my 16" Admiral. You'll see...
Interesting, but, not overly difficult...
Even if your flyback still works, and, I don't think so, it will needto be properly cleanned, and, re coated. Manny waxes would be corosive.
It's a delicate job. But, even if it's open, and, you found open, I'm positive flybak is dammaged beyond repair.
Even replacing flyback, you will need to take current, and, voltage readings on horizontal output to make sure it isn't drawing too much current.
There is also alot more other stuff that there is to do in these sets.
I see one transformer has already been replaced. It's also been messed with. Who knows what else may be wrong?
Checking filament on picture tube on an ohm meter doesn't mean tube is good.
You need a pix. tube tester to find out. If it isn't, where are you going to find a good 12UP4? If not, how are you going to convert the set for a 12LP4?
These are all things to be considered here...
I'm not trying to discourage you. But, this is one of the worst sets you could be cutting your eye teeth on...
And, I replace all bad resistors, and, always dump those sand resistors. Even if they look good, which yours don't, they are prone to corosion inside, and, poor connections.
Other than that, good luck. But, I really reccommend you find another tv to start on....
Bill Cahill

Dang. The only TVs I've worked on are the hard ones: 2 Portholes, GE Locomotive, and a transformer-less Emerson. I think I'll look around for a Muntz or Admiral next time. I've never seen a Muntz and am curious about its minimalist circuitry.

Seriously Bill, you are right. Those TVs you mentioned are difficult TVs to work but if Noisebox is determined and if he engages the experts here on ARF, he can get 'er done.

Carl

I'm not trying to frighten him away. Indeed, I'm glad to see more interest in these old gems of the past. But, you remember the nightmare you had on your Zenith with the bad flyback, then, the continuous arcing problem on hv rect. socket. I'm concerned that if he gets burned out on this nightmare, he may lose interest. I wouldn't want that.
But, you can plainsly see that even if he replaces the flyback, there will be other serious issues to repair.
I'm doubtful I'd want this nightmare, either...
I have enough issues fixing the common nightmares like my RCA 6T74. Sure it's nearly finnished. But, at what cost of time, and, expense?
I have as much in that set as my father paid for the family set when it was new...
Look at all the repairs I had to do on that....
Face it.. It needed EVERYTHING.
Bill Cahill

Bill, you are right -- that Zenith Porthole was a "bear" being my first attempt at restoring a vintage TV. You got to admit it was in pretty sad condition. But, it was one of the most enjoyable projects I have attempted. Certainly did consume several months of my life. My second TV was that little Emerson 639 which was transformer-less and, though tedious because of the cramped space, was much easier to get working than the Zenith Porthole. Just had a chance to pick up a partially working Zenith Porthole, yes another one, but could not make follow though. Now that one would be sweet to restore.

Now you got me scared ... up on my workbench is a GE Locomotive Model 805 awaiting me to recap. One thing I'm going to do this time is re-stuff the Electrolytic cans to free up space underneath the chassis. My Capacitor order is probably being delayed in customs and I'm beginning to get a little impatient.

This is indeed a great hobby.

Carl

Let me put it this way. I've had mine for ten years, and, I have only made sure pix tube is still good. Every time I look at the bottom of that set,I cringe....
Oh, weel. At least I have the original feet. Someday, I guess I'll work on it, unless somebody twists my arm enough for it.
Bill Cahill

Yep, the GE Locomotive 805 is tight. But, I think once I substitute out those bulky 150uf and 60uf Electrolytic's it will open up the chassis for recapping the rest. Got Tom Albrecht's Restoration Notes to reference when I get going on this one.

Carl

Bill, I knew when I got into this TV there was a possibility I would fail--or succeed. The worst case senario is that I have a real cool piece of furniture that is a conversation piece too. I can't lose on this one money wise either since it has all the original parts and the finish is also original. If I keep it for 10 years I'm certain the value will remain.

That said, I stand in awe at the experience you have as well as the collective experience here at ARF--especially in the Television section. I'm a smart guy and I've done a lot in my life. I've also failed miserably too many times to count and I have the scars to prove it. But, I'm a persistent person and failure doesn't scare me. Hell, I've been through two failed marriages with a combined 30 years and I still find the ladies attractive! People have told me many times that I can't do this or that or that I shouldn't do this or that and sometimes they're right. Hearing your words of caution about this particular model--I take them very seriously because you're vastly more experienced than I am, but this is why I'm a member of this forum, to hang out with a wide variety of very smart people. I don't go to bars and I don't socialize to speak of. In other words, the people at ARF are my friends.

And so now I have this amazingly complicated piece of gear that I know almost nothing about. I looked at the schematic and almost peed my pants (not old enough for Depends yet ). There are terms and circuits that may as well be written in the proverbial Greek language as far as my knowledge goes. And, there is dangerously high voltage that if I make the wrong move, it can zap me and throw me across the room! How cool is that? And so--it's man against machine and I've always been up to that challenge, as I'm sure most of you are.

Now, the flyback. Whether or not this one is good, I'm going to pull it and clean it off just to see what it is and what it does. I might look for a flyback tester too since I've been collecting test gear lately. It's the perfect opportunity to learn something. I'll post pictures of it in case someone in the future needs to see what they're up against as well. Here's another ARF TV thread fantasy: I dream that somewhere in the world there is a room where shelves of NOS vintage TV parts are stacked to the ceiling and somewhere in that room is a NOS flyback for the porthole, and next to is is the CRT. This room is unknown because the family has kept uncle Jim's stuff just as he left it when he died in 1955 to keep his memory alive, and now they're ready to sell it.....Like Jimminy Cricket says, when you wish upon a star, sometimes dreams come true! haha! Until then I'll just keep plugging along--this might be a long thread........
Ben

I really like the cabinet styling of your new Zenith, very nice looking set.

Seems like all the early Zenith's used a Thordarson Fly-52 or Fly 53. My Thordarson catalog says Zenith part number S-16191/204 cross to a Fly 53. Schematically the 52 and 53 look identical, so I'm assuming there are mounting differences between the two?

BTW, There's an actual schematic for the 23G24 chassis in SAMS 91A folder 13. Howerver it's a preliminary release, so it's not your typical SAMS with all the part numbers and pictures. Apparently SAMS never seen fit to come out with the complete service info for this chassis.

Here's the flyback all cleaned up. I carefully pulled away all the big sections of wax with a blunt tool and then heated it gently with a blow dryer. The rest came off pretty easy. I don't see any visible burns or smell anything burnt for that matter. I can see why these can't be rewound--That would be insane!

I checked the most obvious terminals and it looks like the primary has very little resistance. From what I understand the primary has some pretty big wires and few windings. The other winding I tested looks like one of the secondaries, which go to pin 2 and pin 4 of the 1B3GT. It appears there are three secondaries. My question would be, on the terminal side of the flyback, the terminals are numbered 1,2,3 and 4. Where else should I measure resistances?

Go for it Ben. Bringing back an old Porthole is not something you can make money on but instead a labor of love and a unique learning experience. Television theory based on Vacuum Tubes is slowly becoming a lost area of knowledge and more of us need to learn from the experts here to better preserve what was once widely known.

Like Bill said, its not the easiest TV to work on ... but who wants to put a lot of time in an uninteresting TV anyway. These old Porthole TVs certainly are eye catching and do attract attention.

Carl

May be good after all, but, it still has to be re insulated.
Need correct wax. Can't use just any wax.
Insulating is crittical.
Without it it will arc...
I stand corrected, and, hope you get it going.
But, it will still be very challenging....
Did you read my very long thread on my RCA 6T74? It will educate you, I guarantee...
So will my more recent Admiral thread. That tv is nearly finnished.
Bill Cahill