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 Post subject: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 7:06 am 
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Location: Riverside, CA
I picked this up in March of 2015 and finally have time to work on it. Pretty dirty and dust on the inside but should clean up well. Here are a couple of photos after I picked it up last year and wiped it down with lemon oil:

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The cage that covers the back was included. Just removed so I could take some photos.

I tested the 19AP4 CRT with my Sencore CR-70 and talked about that in a different thread. Here is a photo of the heater:

Image

I read somewhere that if the filament glows blue like that then the CRT has lost its vacuum. Has anyone else heard of this? I hope not but if that is the case then fortunately I have a spare 19AP4 that tests strong.

So my fist step tonight was to remove the power supply. As you can see it is pretty filthy:

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I have an original Sam's Photofact for this as well as the original Zenith service data.

First thing I plan on doing is checking continuity on the transformer. If that looks good then I plan on stripping the chassis of all parts and coating it with naval jelly. Then repainting it.

I've done several radios but this will be my first TV. However, I've watched a lot of banderson's YouTube videos and have been reading about what it takes to work on vintage TV's for quite awhile now so I have a pretty good grasp of the basics and know where not tot touch so I don't kill myself. I also am a great admirer of Phil Nelson's site!

With work, a wife, 2 kids, and a house to keep up I have a feeling this is going to be a long restoration. Hope we can all enjoy the ride together.

- Geoff


Last edited by Geoff on Aug Thu 18, 2016 9:51 pm, edited 1 time in total.

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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 2:52 pm 
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I read on here once the blue illumination means the ion trap is correctly aligned. I think Phil provided that info.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 7:22 pm 
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Location: Georgia
I hate to be the bad news bearer but the ion trap location has nothing whatsoever to do with the blue gas conduction glow within your CRT.
It has leaked air and therefore now is "gassy" rather than a vacuum so it acts somewhat like a neon sign. Must be replaced in order to correct.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 7:25 pm 
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Location: Georgia
The photo is rather dark -----is that the CRT neck that is glowing or one of the 5U4's? If it one of the 5U4's then that is quite a relief and you just have power supply issues which are easy to fix.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 7:48 pm 
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You didn't say what the emissions were, if the emission and cut off is good then the tube is most likely good.
I have seen this blue glow in CRT's before, it looks like the same blue glow you get on some power tubes when they are under a load.
A gassy tube will glow down inside the elements (usually a more Lavender color), a good tube will glow on the inside surface of the glass, this appears to be on the surface of the glass and right where the opening in the gun is at.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 8:04 pm 
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Here's the thread where the 19AP4 was tested but it trails off at the end. How did it test after running for a couple hours ?

viewtopic.php?f=3&t=301175


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 8:26 pm 
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bandersen wrote:
Here's the thread where the 19AP4 was tested but it trails off at the end. How did it test after running for a couple hours ?

viewtopic.php?f=3&t=301175

That was the testing of the spare 19AP4 that I have in my DuMont RA-112. I let the heater run for a couple of hours on that one and retested and it was still strong.

The original post showing the blue glow in the Zenith (above) was in a topic I started about a 21EP4. Follow this link and then scroll half way down to the photo of the Zenith. The conversation on the 19AP4 starts there. In the second to last post I mentioned I might leave the heater on overnight but I never got around to it. Will look at doing that this weekend.

http://antiqueradios.com/forums/viewtopic.php?f=3&t=279181

- Geoff


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 9:46 pm 
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Interesting. Sam’s says this part is R61 (10K, ½ W resistor):

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In the picture I took it looks a lot like a wire wound resistor with a higher wattage than ½ W. But the literature does not call it out as a wire wound. It does call out R60 as a wire wound.


Last edited by Geoff on Aug Thu 18, 2016 9:50 pm, edited 2 times in total.

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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 9:48 pm 
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Last time I saw that much blue around CRT filaments, the filament burned itself out within a minute or so.

.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 9:59 pm 
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Geoff wrote:
Interesting. Sam’s says this part is R61 (10K, ½ W resistor):

In the picture I took it looks a lot like a wire wound resistor with a higher wattage than ½ W.


What does it measure?

.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Thu 18, 2016 10:07 pm 
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wiscojim wrote:
Geoff wrote:
Interesting. Sam’s says this part is R61 (10K, ½ W resistor):

In the picture I took it looks a lot like a wire wound resistor with a higher wattage than ½ W.


What does it measure?

.

Don't know. I'm at work right now and will measure it tonight.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Fri 19, 2016 1:25 am 
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wiscojim wrote:
Geoff wrote:
Interesting. Sam’s says this part is R61 (10K, ½ W resistor):

In the picture I took it looks a lot like a wire wound resistor with a higher wattage than ½ W.


What does it measure?

.

I checked what Sam's is saying is resistor R61 and compared it to the 1951 Zenith Television Service Manual. The P/N for this resistor in the Zenith manual is R27. R27 is listed as a 10K but says that it is a 5W wire wound resistor. That matches the photo in Sam's and the photo from my chassis. So it looks like the wattage is a misprint in Sam's. I still need to measure the actual value tonight.

Regardless, the one in my set looks pretty crispy.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Fri 19, 2016 12:12 pm 
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Geoff wrote:
wiscojim wrote:
Geoff wrote:
Interesting. Sam’s says this part is R61 (10K, ½ W resistor):

In the picture I took it looks a lot like a wire wound resistor with a higher wattage than ½ W.


What does it measure?

.

I checked what Sam's is saying is resistor R61 and compared it to the 1951 Zenith Television Service Manual. The P/N for this resistor in the Zenith manual is R27. R27 is listed as a 10K but says that it is a 5W wire wound resistor. That matches the photo in Sam's and the photo from my chassis. So it looks like the wattage is a misprint in Sam's. I still need to measure the actual value tonight.

Regardless, the one in my set looks pretty crispy.


No doubt, the wattage escaped the editors. Maybe it interpreted as .5 watt by the typist? But 10 watts wire-wound makes sense. And that is an easy resistor to find and replace.

As for stripping the chassis, it is your set to do with however you wish. I might just say that it really doesn't look all that bad and I might be tempted to just do a thorough cleanup and restoration. But however you proceed, it should be a very nice set. Enjoy!

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Don


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Fri 19, 2016 6:01 pm 
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Question about electrolytics. The "rule of thumb" I read elsewhere is "Do not use more than 80% higher (or 20% lower) than the original uF size." I need to replace a 40uF, 450V electrolytic.

A 39uF electrolytic through Digi-Key is only $1.85 (P/N 565-3526-ND) and is rated for 12000 Hrs @ 105°C. The data sheet says it is "used on high reliability applications such as electronic ballast (Lighting) and Switch mode power supplies".

A 40uF, 450V electrolytic through Mouser is $13.50 (Mouser P/N 75-TVA1712) and I could find no information about the number of hours it is rated for. The data sheet says it is "ideal for application in TV sets, auto radios, radio-phone combinations, electronic testing equipment".

Any issues with going with the Digi-Key 39uF? I would think not since the originals probably had a tolerance of +/- 20% and both the Digi-Key and Mouser units are rated at +/- 20% but I just wanted to check before ordering. Especially since the Mouser unit says it is "ideal for application in TV sets".

Sorry for being a bit long-winded but I want to make sure I buy the right components.


Last edited by Geoff on Aug Fri 19, 2016 8:21 pm, edited 1 time in total.

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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Fri 19, 2016 6:06 pm 
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Also, I removed the capacitors and resistors last night. Referring to the picture below, R61 (wire wound) was open and R60 (wire wound) just crumbled in my hand. I did not test R62 yet. The others are just carbon comps so I'll replace them as a matter of course. Still need to test the tubes.

Image


Last edited by Geoff on Aug Fri 19, 2016 7:36 pm, edited 1 time in total.

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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Fri 19, 2016 6:35 pm 
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DELETED.

Figured out the answer to dumb question.


Last edited by Geoff on Aug Sat 20, 2016 5:25 am, edited 3 times in total.

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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Fri 19, 2016 8:16 pm 
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47uF is most widely available modern equivalent to 40uF. It's well within specs of the original and you'll find plenty to choose from at reasonable prices.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Sat 20, 2016 12:48 am 
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Don Cavey wrote:
As for stripping the chassis, it is your set to do with however you wish. I might just say that it really doesn't look all that bad and I might be tempted to just do a thorough cleanup and restoration. But however you proceed, it should be a very nice set. Enjoy!

There is a fair amount of rust on it. You can see a little of it in the photos I posted. I can hit just those spots with Naval Jelly but would need to put something over it to protect it. Do you have any recommendations?


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Sat 20, 2016 1:26 am 
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When I did my porthole (getting ready to do the second one), I used Rust-Oleum Rust Stripper from pepboys and applied it with a small cheap artist brush. It worked well for me. It was only $5.00.


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 Post subject: Re: My Next Project - 1951 Zenith H2445R Tennyson Porthole
PostPosted: Aug Sat 20, 2016 12:52 pm 
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Geoff wrote:
Don Cavey wrote:
As for stripping the chassis, it is your set to do with however you wish. I might just say that it really doesn't look all that bad and I might be tempted to just do a thorough cleanup and restoration. But however you proceed, it should be a very nice set. Enjoy!

There is a fair amount of rust on it. You can see a little of it in the photos I posted. I can hit just those spots with Naval Jelly but would need to put something over it to protect it. Do you have any recommendations?


clsoca wrote:
When I did my porthole (getting ready to do the second one), I used Rust-Oleum Rust Stripper from pepboys and applied it with a small cheap artist brush. It worked well for me. It was only $5.00.


I was thinking along the lines of this statement above. "Q-Tips" are excellent for small jobs. You can dab it on, and then throw the tip away after using it. Q-Tips are also good for spot touch-up painting as well. Naval Jelly works well also.

I guess I was just trying to save you a lot of work and help avoid a possible issue with the reassembly of the chassis. But if you are up for it, for sure, go for it. That chassis seemed to have only a few rust spots, not major damage like some that have shown up here.

Also, as for that "Candohm" metal resistor that is mounted to the chassis R-62, you could get a good metal wire-wound replacement for it and attach it to the chassis (for heat sink purposes). They are notorious for the paper inside going bad and the wire inside shorting to the metal case. Actually, those sand resistors are rather inexpensive today and the quality that we have is far superior to what Zenith had available to them in the 50s.

This should be a nice set when you are done. As for the CRT, since everything else seems to be in good shape, it may be worth moving forward and replacing it (CRT) if it turns out bad. But don't go by my suggestions because with electronics and cars, what is most important to me is excellent cosmetics. The insides, whilst maybe expensive or elusive, can eventually be located. No, you most likely won't make money on the project. But if that is what you really want, think of the satisfaction when you sit down to watch an old B/W show with friends or family (or by yourself :wink: ). Just me...

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Don


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