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 Post subject: Zenith Porthole TV - G2438R Restoration ...
PostPosted: Oct Mon 19, 2009 11:54 am 
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Location: Advance, NC USA
Just obtained a Zenith Porthole TV - G2438R.

Don't have a lot of experience working on TVs but would like to try my hand with this one.

Anyone have Schematics or know where I can obtain them?

Any tips on restoring this TV?

Thanks

CW


Last edited by cwmoser on Nov Mon 16, 2009 6:13 pm, edited 1 time in total.

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 Post subject:
PostPosted: Oct Mon 19, 2009 12:15 pm 
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Location: Tampa FLA
I'm not overly experienced, but the first thing I would do is get the Sams Photofact for the TV. In a set that old, you are going to wind up replacing all of the electrolytic caps, and paper capacitors….Followed by out of tollerance resistors.

Take things apart and get a good camera, and take bunches of hi-res pictures…so you can blow them up if you need to refer to specific connections. You can draw diagrams too. Do some searches and read as much as you can about these sets. From what some have told me, these can be a little tricky. But I'd think any TV is a little tricky when we are used to replacing caps in radios and such.

There are a lot of really helpful and knowledgable folks on this this TV forum….if you listen to them…you'll have a working set before long.

I am shooting for a Zenith Porthole myself…Just have to turn one up. Good Luck! And keep us posted!
Tim
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 Post subject:
PostPosted: Oct Mon 19, 2009 4:26 pm 
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It's in Sams 91A-12.


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 Post subject:
PostPosted: Oct Mon 19, 2009 4:46 pm 
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How about some pictures?
Bill Cahill

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 Post subject:
PostPosted: Oct Mon 19, 2009 5:21 pm 
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Here's the link to the previous discussion, which in turn has links to my restoration of a G2439. The Rider TV manuals have the complete data, in vol. 4.

http://antiqueradios.com/forums/viewtopic.php?t=118153


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 Post subject:
PostPosted: Oct Mon 19, 2009 6:29 pm 
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Alan's references tell it all. Zenith portholes are quirky and built somewhat different from other major brands of the same age. The tuner alone is huge, the size of a small table radio or a 1960's solid state portable TV.

Some find Zeniths quite frustrating to work on but they do work well and have a unique look, as there were not too many other brands making sets with full round viewing screens.

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 Post subject:
PostPosted: Oct Mon 19, 2009 11:07 pm 
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Here is a picture of my G2438R Zenith Porthole TV - it looks complete.
Cabinet in pretty good condition. Need to repaint the bezel with correct colors. Have not delved into the insides just yet - its in my shop and its likely to spend a lot of time there being worked on before it can move into the house.

Where can I purchase the Sams Photofact for this TV? Like to look at the schematics to get an idea of what I am getting into.

Thanks

CW


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 Post subject:
PostPosted: Oct Mon 19, 2009 11:26 pm 
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Location: Tampa FLA
That is a beautiful set! I am envyous. Do a search on google for the model number and photofact...a site should come up. Also ebay would probably have one somewhere.
Tim
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 Post subject:
PostPosted: Oct Tue 20, 2009 12:06 am 
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The Sams folder is 98-17. My recollection is that it's not an exact match for the 24G24 chassis I had, and I found more information in Rider TV4.


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PostPosted: Oct Tue 20, 2009 1:17 am 
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Almost the same as mine, however, my cabinet has the phono & radio in it.

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 Post subject:
PostPosted: Oct Tue 20, 2009 8:48 pm 
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I had 2 of those sets, 2 different chassis. One set had the 24G24 chassis with the separate power supply, the other had a single chassis. I hope your 16EP4 is good! If not, you might be able to make 16GP4 work if you flare open the yoke a little.


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 Post subject:
PostPosted: Oct Tue 20, 2009 9:03 pm 
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My Porthole has 2 chassis. All the tubes appear to be there except for one in the lower chassis. I assume the lower chassis is like you mentioned the Power Supply - it has a large transformer on it.

What do mean when you say "you might be able to make 16GP4 work if you flare open the yoke a little"??

I have not pulled the chassis yet. They need some cleaning up to get all the crud off of them.

My plan is to test the Picture Tube first - hopefully my Precision 10-12 tube tester will do that, then if the tube is good do a complete recap before applying power.

I'm looking for all the advice I can for this set. I dabbled with TV's in tech school 40 years ago and I'll have to rehone my skills. I know there is high voltage on this TV and know I need to ground the picture tube anode after removing power to work on this. Refresh me -- is this basically connecting a shorting wire between the Chassis and the anode wire? Would it be better to use a resistive short?

Thanks

CW


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 Post subject:
PostPosted: Oct Tue 20, 2009 10:06 pm 
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Zenith Porthole TV – 1950:

Purchased October 17, 2009 at Mebane Auction who obtained it from an estate in Hickory, NC.

Some observations after removing the metal back cover:

Wood cabinet # stamp: 2438RZ1

Main chassis # stamp: 2438RZ1

Sticker on inside of cabinet with tube layout: TV Chassis # 24G26Z1
275 watts

Black Metal 16” Picture Tube: 16EP4A


Notes:

Missing 5U4 tube on power supply chassis - all other tubes appear to be there.

Some rust on chassis

Lot of crude on chassis

Speaker appears to be in great shape.


CW


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 Post subject:
PostPosted: Oct Tue 20, 2009 11:31 pm 
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I'm a little stumped here. Sams 91-A is supposed to be the correct manual--it isn't. Only the schematic is in that set. Alan Douglas says the G2438R chassis is in 98-17, but that manual does not list the G2438 chassis.
I was going to offer to make a copy for CW, but now I don't know what to copy.


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 Post subject:
PostPosted: Oct Tue 20, 2009 11:38 pm 
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Main Chassis:


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 Post subject:
PostPosted: Oct Tue 20, 2009 11:39 pm 
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Power Supply chassis:

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 Post subject:
PostPosted: Oct Wed 21, 2009 1:56 am 
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Johnnysan wrote:
I'm a little stumped here. Sams 91-A is supposed to be the correct manual--it isn't. Only the schematic is in that set. Alan Douglas says the G2438R chassis is in 98-17, but that manual does not list the G2438 chassis.
I was going to offer to make a copy for CW, but now I don't know what to copy.


I have the Sams 91A that is supposed to be for my porthole. And as mentioned above, it is only a schematic. I will be glad to scan it for you if you wish. However I can't do it until after Saturday because I am flying out to Louisiana tomorrow, returning Saturday. Just let me know...

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 Post subject:
PostPosted: Oct Wed 21, 2009 3:24 am 
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Go by the chassis number, not the cabinet model.

Quote:
Sticker on inside of cabinet with tube layout: TV Chassis # 24G26Z1


The 24G26 uses parallel heaters and a real power transformer, according to the Rider TV manual vol.4 (p.38). The schematic is on page 4-42. Other data is the same as the 24G24, which is either in Rider or Sams.


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 Post subject:
PostPosted: Oct Wed 21, 2009 3:34 am 
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Right, the Sams # is 91A-12. The chassis number is the 24G26, the model of the TV is 2438R. I've seen 3 different chassis in that style cabinet. The flyback was replaced, as it was originally mounted underneath the chassis. The 16EP4 CRT is a 60-degree tube, and if bad, can be a stinker to find a replacement. The 16GP4 is a 70-degree tube, and are easier to locate. If you put a 16G in your set, I expect you'll have neck shadow issues, because the yoke can't be moved forward enough. One ol' gent I knew used to bake the yoke in an oven, then force it onto a pop bottle to flare open the front a little. I may be able to sent you a 70-degree yoke from a '51 model also. We'll cross that bridge later, first check your CRT.


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 Post subject:
PostPosted: Oct Wed 21, 2009 3:46 am 
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Alan, looks like you're correct on the parallel heaters, as I can see a 6BQ6 H out. Did they do away with the hot chassis as well?


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