1949 Zenith Porthole Restoration
 

Hi there,

This is my first post and I put it in the intro section, but it may not have been read there. I'm restoring a 1949 Zenith Porthole, model 28t926. I'm having to restore everything, including the case. It's missing the shield over the tuner, but maybe I can make one. The flyback tests bad on my eico tester, does anyone have an extra one? I also wondered if having the switch to turn the tv screen from full screen to partial screen was an option? My set doesn't have one and I thought they all did; my other two portholes do. It was free, so I couldn't pass it up! I also need the maroon colored knobs. I only have the blonde set. I've reveneered the top and sides. Still a work in progress. Any help would be appreciated!

Thanks,
Scott

Hello Scott,
I like it , it looks rough but once all the loose veneer is glued back down and the set is cleaned up it'll look alot better. I have the 28t960 (same chassis I believe) I don't believe these sets had the screen size option. I think that started on the 1950 sets.I do have a maroon volume knob on mine and i'll look to see if I have any of the other maroon knobs. Would you trade a maroon volume knob for a blonde one?

Hi Paul,

Thanks for your help. As you can seen in the picture, I've reveneered the top and side. After about a bottle of glue, I've glued the set back together. Now I have to make the slats for the side and the triangular piece with cutouts at the top side. I've always wanted a 1949 Zenith, but they're pretty hard to find. I notice my model has the nameplate at the bottom, where as the other similar 1949 sets its at the top. Once I finish making the remaining pieces ill refinish it. Yes, I'd trade a blonde knob for a red one. I will most likely not find a blonde porthole, they're even harder to find. I've recapped the seperate power supply caps, but zero high voltage. My flyback looks sad tests sick. This may be my biggest roadblock...finding one.

Thanks,
Scott

Sounds like you know yer way around Portholes pretty well... I LOVE how they totally freak today's jaded kids out.

I have the 10" version of this set, it's flyback was toast also, I'm assuming here that your set uses the same chassis with the Fly mounted on top?

Since it has the same Sweep tubes as the RCA 630 and similar I was able to swap in a common RCA FLY-1 flyback with no wiring changes, other than replacing the resistor network in the yoke to the RCA values, it works great, runs cool and is a much better flyback than the Zenith.

If I can find the pictures of the swap I'll post them.\

Ahh, found it.
http://vintagetvsets.com/temp/arf/ze...ybackfinal.jpg

And the thread about it:
http://www.antiqueradios.com/forums/...yback&start=20

Nice looking set. Keep us posted on your progress.

Eric,

That is an interesting idea! Now I've got to find a fly-1, because I don't have one. That will hopefully be easier to find. I added s picture of the original fly to show you how sad it is. I've also got to restring my contrast and tuning dials also, but that shouldn't be too hard.

Thanks,
Scott

The case is starting to take shape and about ready to make the missing slats and the top molding along the right side with vent cutouts.

Scott

This set is off to a great start. I like seeing a cabinet that would otherwise be kindling become whole again.
I did veneer on a '36 GE console radio and was not able to hide the sheet joints

is that fly shot or just dirty and cook ed

It fails the continuity and the short test on my eico 944 flyback and yoke tester.

Scott

The face is all glued back together. Finally ready to strip the case!

Scott

The control doors cleaned up nicely, just waxed them. The screen escutcheon I had to repaint as close to the original color as I could find.

Are you testing it in circuit? I'm pretty sure it has to be completely disconnected.

It doesn't look all that bad, I wouldn't give up on it until you get the set fired up and see if it works. Mine actually shot sparks out of it so I was pretty sure it was shot. :yes:

I tested with the eico tester with the HV rectifier and horizontal output tubes out of their sockets. I have fired up the set, after I replace the power supply caps and nothing...

Scott

I also didn't have high voltage on first power up on mine. Turned out it was missing the phonevision jumper plug on the back of the chassis. It took me at least an hour of curcuit tracing to figure that out.
I'll dig through my stuff and see if I have any more maroon knobs for it.

You know, I never looked at that. I'll definitely see if it's that, I know what you're talking about.


Thanks,
Scott

I looked at the chassis tonight and it does have the phonevision plug in its correct socket at the back. Back to the drawing board. A friend of mine may have a replacement flyback for me. I'll recoat the picture tube once I see some progress. It's a 12lp4 and tests ok.

Scott

I've seen worse looking flys work, and nicer ones dead, and I've had my EICO fly tester lie to me occasionally....Case in point don't judge a book by it's cover. Get the H osc thru HV sections recapped and the osc. tuned, then you'll have grounds to declare it dead with certainty.

This looks like one but condition unknown. No affiliation.

http://www.ebay.com/itm/121650338736...%3AMEBIDX%3AIT

That looks like one but there are a lot of them that look the same. If anyone has a 49 Magnavox Sams they could check and see what fly it used that should tell.
If it uses the same sweep tubes and yoke it'll probably work.

There were a lot of sets from 46-49 that used the Fly 1.

A friend of mine gave me a few flybacks that are listed as suitable replacements for my set. One being a fly-53. I will recap the horizontal section as suggested first, to see if any life is shown left from my original flyback. If still nothing, then I'll try replacing with one of these three.

Getting ready to recap the horizontal section and I notice that the Sams listed for this model doesn't even match. I can replace what I see in the set, but how do I know what the sand coated resistors are when the sand has fallen off with the markings?

Try this schematic, Rider 3 page 13-14. Wide band if revised chassis
http://www.earlytelevision.org/pdf/z...f20-rider3.pdf
This one matched my chassis.

Thanks for the help. I forgot I actually had a partial set of Rider's book, including that volume. I'll study it and see if it matches my set.

Ok,

So I'm beginning recapping and resistor checks on this set. Many sand coated resistors, luckily most still have part numbers on them so I can reference what it is on the schematic. There's one that is missing all of its coating. That should be fun tracing that part back. I'm going to replace as much as I can, with what I have on hand, then order the rest. Three electrolytic cans are hidden on top of the chassis, underneath the yoke assembly. So I had to remove them to access these cans.

This is the resistor in question, missing all of its sand coating. Another was like it, but still had the side with part number on it. That one was completely open. Yes I can trace them back on the schemstic, but it's a heck of a lot faster if I can look it up under the resistor part values on the schematic.

Ok,

I've replaced the few caps that I had left over from a prior set I restored. I placed an order for the remaining caps and some open power resistors that were sand coated. I also ordered the 20 watt power resistor that was completly open off of ebay by Clarostat. Now I sit and wait for the parts to arrive.

Parts Arrival
 

Parts came today, time to get busy!!

Cap replacement is coming along. I also replaced two of the sand coated power resistors. I'll finish them and replace the three electrolytic cans under the yoke assembly.

Nice progress. Those sets are very cool.

We have life!
 

Ok,

I changed the remaining three electrolytic canned capacitors and the power resistors and I was rewarded with a one inch line on the screen! So at least we know the flyback isn't gone. Now to figure out why I'm getting insufficient height. If I turn brightness up or down, the raster will disappear.....

Nice work! Have you tried carefully adjusting the ion trap?

You've come a long way and you're getting really close!

-Clark

It didn't have an ion trap on the crt when I got it. I can try one from another set and see if there's any change. Thanks!

If it doesn't have one and you see something on the screen, it doesn't need one. Probably an aluminized CRT like a 10FP4.

Finally some progress
 

After swapping out a couple of tubes I was rewarded with a picture and audio! It only has 4000volts at the second anode, but definty progress. Now I have to figure out my insufficient high voltage priblem.

Your set is looking great and what a nice job you did on the cabinet replacing the veneer. Does it have a Rouland picture tube?

Thanks Damen.

My set actually has a GE 12kp4 tube in it. Still working on where my high voltage is being pulled down. I love the looks of your set, especially with that brass trim in the grill cloth area.

Scott

Hmm. If it has a 12LP4 as stated in an earlier post, that would normally require a double field ion trap. Probably a rebuild with a straight gun in it.

Looks like your getting close!

-Clark

Thanks!! Hope you get the one like it from your friend. Be cool to have both. I know a lot of things could cause voltage to be low good luck on that.