Welp-

I picked up a Zenith Porthole TV over the weekend. In my "introduction" thread I mentioned how I came upon this TV.

Basically, I brought it home, set it in the garage, blew it out with my air compressor, and brought it in the house.

I still don't know what model it is, I haven't looked that close yet :). The previous owner told me that it doesn't work, and he never plugged it in. The owner before him told him it didn't work. Nobody really knows to what extent it "doesn't work". I only paid $40 for it, so no biggie if I can't get it working. I just know, after reading many posts on here, I'm not going to plug it in and "see what happens"!

I have a lot of modern electronics experience, but I have never worked on a tube set before. I look forward to you guys helping me out with this. I will probably start with a full recap before I try anything else.

Here's a pic of it. I will probably begin working on it this week or this weekend. Are there any quick tests for the CRT to be able to tell if it's any good before I go through the trouble of recapping?

Thanks fellas!

I can honestly say I don't recall ever seeing a 12" 1951 porthole console before. Nice find!

Absent a CRT tester, about all you can do is check the CRT filament pins for continuity. A few ohms means the filament is intact, infinity means it's a dud. You can find tube data sheets here:

http://tubedata.tigahost.com/tubedata/

It might have an intact filament but still have weak emission, of course.

Phil Nelson
http://antiqueradio.org/index.html

...

Here's a pic of it. I will probably begin working on it this week or this weekend. Are there any quick tests for the CRT to be able to tell if it's any good before I go through the trouble of recapping?

Thanks fellas!

That's one nice looking set :thmbsp:

If you have a multimeter, you can check for filament continuity on the CRT. Those will be the pins to either side of the socket key.

Nice set! I love Portholes.

That should be a 12UP4 tube, this is a metal/glass construction tube, they tend to be bad more often than all glass tubes because of leakage however the smaller ones seem to have a better track record than the larger sizes. (Search 19AP4)

You can check to see if it's still under vacuum by removing it from the set and looking for the Getter Flash on the neck of the tube, shiny and dark indicates it's under vacuum, white and powdery means it's gone to air.

I notice some discoloration on the screen in the upper right side, I'm presuming it's just dirt but I'd inspect it closely.

Handle the tube very carefully, be very careful not to bump it on the rim around the screen as that is it's weakest point for cracking.

Also note that when the set is operating the entire bell of the CRT has 10-12 thousand volts on it.

I'd also take a good look at the Flyback transformer, they are a known trouble spot on these Zeniths, just visually inspect it and see if it looks burnt.

I can honestly say I don't recall ever seeing a 12" 1951 porthole console before. Nice find!

How can you tell it's a 1951?

What part of the country are you in? Maybe somebody on here is close enough to lend you a crt tester. If we can narrow down which model it is I might be able to dig out a Sams Photofact to send you.

I notice some discoloration on the screen in the upper right side, I'm presuming it's just dirt but I'd inspect it closely.


It only looks that way in the picture, in person the screen looks uniform. It must be a reflection or something...

What part of the country are you in? Maybe somebody on here is close enough to lend you a crt tester. If we can narrow down which model it is I might be able to dig out a Sams Photofact to send you.

I am in north-central Ohio.

Are you familiar with the ETF museum in Hilliard? (Just outside Columbus.)

http://www.earlytelevision.org/index.html

Phil Nelson

Nice looking set. I would like to have one myself. Good luck!

It is a 1951 model H2250R (chassis 22H20). The escutcheon is the giveaway on the model year. I used to have one and have a web page on the restoration of it: http://www.angelfire.com/electronic2/radiosean/tv/Zenith_H2250R/porthole.htm It originally had a 12UP4 CRT in it but mine had a 12LP4 in it. Zenith had a kit to convert the chassis from the metal cone tube to the glass tube. The factory service manual and Rider's service information are available on the ETF website: http://www.earlytelevision.org/tv_schematic_diagrams.html

Here is my 16" 1951. As you can see, even though the tube is bigger, the escucheon design is the same.

Sean- Awesome job on yours! Thanks for the links, I am sure that will help.

ggregg- Nice Porthole (sounds strange to say to another man, lol). Does yours work? One like yours came up on craigslist when I got home from buying mine. If I had space, I'd buy it too :)

There's a leather-covered 10-12" 1950 tabletop model porthole Zenith-I can't remember the model name-that has a video on Youtube of Liberace playing "Nola" that I've lusted over for years...The TV, NOT Liberace....(grin) Just somethin' about a Porthole, & the whole "1950" thing going on about it...But I guarantee you, put a well-restored Porthole alongside the latest whiz-bang HDTV widescreen video display unit-I shudder to call 'em TVs anymore-and see which one generates the more grins & comments.

Looks like 1951 may have been the transition year between the porthole and rectangular picture tube Zenith sets: TV0832-lrg.jpeg
http://library.duke.edu/digitalcollections/images/adaccess/TV/TV08/TV0832/TV0832-lrg.jpeg

-Steve D.

Sean- Awesome job on yours! Thanks for the links, I am sure that will help.

ggregg- Nice Porthole (sounds strange to say to another man, lol). Does yours work? One like yours came up on craigslist when I got home from buying mine. If I had space, I'd buy it too :)

Yes it works kinda. When I bought it, I did some preliminary checks and then plugged it in and brought the voltage up very slowly with a variac. I have a bright raster so my HV section is working and the picture tube seems fine which are the main issues with these. The radio and phonograph both work. I've only bought one old TV that actually "worked" OK when I bought it (1953 Crosley). They all need paper and usually electrolytic capacitor replacement, usually a tube or six, and usually some other parts. I've been working on a DuMont RA-109 all winter that I finally got going a couple of weeks ago. It still needs a little tweaking but the worst is done. Dozens of caps and 5 tubes including a picture tube, which I really lucked out on. Now I'm working on a 10" Admiral and then the Zenith. Good luck on yours. It's a cute little set and you got it at a great price. I paid a lot more than that for mine.

OK, I measured the resistance on the two CRT pins either side of the socket key, and it showed some resistance, so that's good. Now I have another question- is it normal for the CRT connector to be loose? I can wiggle the plastic part back and forth about 1/16" inch.

I got the chassis pulled out, and setting on my bench. Getting the knobs off was the hardest part!

Now- how do I position this so I can work on the bottom? Any direction I would tip it would put pressure on something delicate... Any ideas?

What was Phonevision?

Are you familiar with the ETF museum in Hilliard? (Just outside Columbus.)

http://www.earlytelevision.org/index.html

Phil Nelson

Nope, I never had heard of that. I am happy to see it's only about an hour away. I will certainly be paying them a visit! Great site too!

Phonevision was an idea that Zenith had, which would have been sort of like cable TV, or maybe even the internet! It never took off, though.

The crt base shouldn't be loose, but many/most of them are. You can use some glue or tape to hold it tight-there are some suggestions on this site somewhere as to what works best. I haven't tried to fix one with glue for a long time. Just be careful that you don't wiggle it around so much. The wires coming out of the neck tend to be brittle and can snap off even with the glass-not good!

The museum is well worth the visit, and there are several VK members scattered around the state. Maybe one could give you a hand with a crt test?

Am I correct that the crt is strapped to the chassis on this model? I will usually place them on their side gingerly, maybe with an old towel under the crt. Make sure the crt is strapped down tight so it doesn't shift when you move the chassis over. On some I have used a pair of clamps to hold the chassis down to the workbench (in my case, and old desk) while working on it. The crt is the main thing you have to keep an eye on-I don't think you will hurt anything else.

Nope, I never had heard of that. I am happy to see it's only about an hour away. I will certainly be paying them a visit! Great site too!
ETF is just about the center of the universe for TV collectors. The annual convention is coming up this spring. It's fun and educational -- I have been going for years. You can pick the brains of some very smart & knowledgeable people and the swap meet & auction typically have some good deals on old TVs.

Phil Nelson

... Now- how do I position this so I can work on the bottom? Any direction I would tip it would put pressure on something delicate... Any ideas?

I predicted that I would need an easy way to mount the chassis when I restored my Porthole TV - so I wanted a comfortable way to position the chassis. I took some strips of wood and made the following:

http://www.cerant.com/ZenithPortholeTV/22%202010Jan09%20-%20Powered%20up%20first%20time/PoweredFirstTimeFront-800.JPG

I used a test CRT in place of my 16" picture tube. In the photo above I used an 8AXP4 tube until I got a picture. The chassis stand I made is bolted to the chassis and allows me to rotate it to a comfortable position to do recapping - here it is rotated to a comfortable position for working on the bottom of the chassis:
http://www.cerant.com/ZenithPortholeTV/18%202010Jan02%20-%20Resistors,%20replacing%20out%20of%20tolerance/BigGuns2.JPG

I brought in some help to test for out of tolerance resistors:-)

My suggestion is to take lots of detailed pictures of your progress.

Carl

bgadow - Thanks for the tip on clamping it to the bench, worked line a charm! I've owned this thing for over a week and I finally get to see the underside of the chassis!

Now, I think my flyback may be burned up. Remember guys, I don't know what an old flyback is supposed to look like, but I bet it's not supposed to look like this! What do you guys think? Is it shot? If so, anybody got a good one?

Also, one of my "sand" resistors is completely missing it's "sand" coating and the windings are torn up (mouse damage, I assume). How can I find this value?

There's a couple other chewed up mystery devices, but I'll get to those later. Here's the flyback- what do you think?

http://midohiovideo.redirectme.net/zenith/zenith1.jpg
http://midohiovideo.redirectme.net/zenith/zenith2.jpg
http://midohiovideo.redirectme.net/zenith/zenith3.jpg
http://midohiovideo.redirectme.net/zenith/zenith4.jpg

It's hard to tell with all that crap around it, but it looks to me like the wax around the outside may have just flaked off with time. It's possible to coat flybacks, I used acetate free silicone on one of mine and it worked great.