Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Early Color Television

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 06-03-2015, 08:38 PM
iong iong is offline
VideoKarma Member
 
Join Date: Apr 2014
Posts: 102
Rca or zenith

Which roundie has the better picture? 60's Zenith or RCA? Will a Zenith 29jc20 look as good as an early 60's RCA. Trying to decide if I should restore or sell.
Need some advice,
Perry
Reply With Quote
  #2  
Old 06-03-2015, 08:57 PM
bgadow's Avatar
bgadow bgadow is offline
VideoKarma Member
 
Join Date: Oct 2003
Location: Federalsburg, MD
Posts: 5,814
Chevy vs Ford, Coke vs Pepsi. Open to much debate. The Zeniths I've seen seemed to be better built but, from that era, I'd say RCA had a slight advantage in pictures. A tough call because individual sets tend to have big differences, especially at 50+ years out.
__________________
Bryan
Reply With Quote
  #3  
Old 06-03-2015, 09:40 PM
jbattles's Avatar
jbattles jbattles is offline
jbattles
 
Join Date: Sep 2012
Location: Ellijay, Ga
Posts: 168
Go with the Zenith! It will not take much to restore. Mostly just repairs are needed, but like anything make the jug is good and it produce a nice picture.
Reply With Quote
  #4  
Old 06-03-2015, 09:52 PM
old_coot88 old_coot88 is offline
VideoKarma Member
 
Join Date: Sep 2009
Posts: 2,541
Regarding a Zenith roundie, the very first thing I would determine is whether its 'efficiency' coil is wound on a brown phenolic form (good) or the later whitish, semi-translucent plastic form (bad). If the latter, I would absolutely pass on the Zenith. The form crystalizes and falls apart from heat and age, This detunes the coil, causing the H.output tube current to skyrocket, rendering the TV set unusable. And those coils are near-unobtanium.
(The blue coils on the convergence panel usually suffer the same crystalization problem.) Earlier Zeniths used phenolic forms here as well as in the eff. coil (good).
Reply With Quote
  #5  
Old 06-03-2015, 10:54 PM
Jon A.'s Avatar
Jon A. Jon A. is offline
Don't mess with Esther.
 
Join Date: Jun 2013
Location: Canada
Posts: 4,267
Did you know that is Zenith's first color TV chassis?

Anyway, I'd say restore it, but I give preference to less-common sets.
Reply With Quote
Audiokarma
  #6  
Old 06-04-2015, 01:14 AM
Tubejunke's Avatar
Tubejunke Tubejunke is offline
VideoKarma Member
 
Join Date: Apr 2003
Location: Martinsville, VA
Posts: 1,823
Quote:
Originally Posted by old_coot88 View Post
the very first thing I would determine is whether its 'efficiency' coil is wound on a brown phenolic form (good) or the later whitish, semi-translucent plastic form (bad). If the latter, I would absolutely pass on the Zenith. .
This problem was the first of a line of heartbreaking events that came along with my bringing home a Zenith 5111. Looking back now, nothing was any real catastrophic failure. I believe that the crusty (brown) form did cause several other issues which had to be addressed due to the high current in the horizontal output circuit.

The big problem was that at the time there were two possibles of retailers with replacement coils known to exist; one being Moyer Electronics and I can't recollect the other which is who I ended up getting mine from for ten bucks more than Moyer wanted. When I began posting about this problem Moyer had three in stock. I waited about a week to order and someone had bought ALL of them. They told me they hadn't sold one in years till that week! Luckily they were nice enough to give me the name of this other place who had one and I had to jump through hoops to get them to send it to my house. Turns out that they had quit sending out small orders to jobbers like TV repairmen years ago and had evolved into some larger business model, but they still had the inventory and were nice enough to accommodate me.

Now what they sent was an N.O.S. Thordarson replacement and it was the "whitish, semi translucent" part that OldCoot said are bad. Being new like it is, I don't have a fear in the world of it breaking apart on me. Will it last as long as the original didn't? Who knows, but I am happy beyond happy to have what seems now to be nonexistent on the market. The true sad part is that there must be tons of these chassis sitting around in people's hoards and I couldn't get anyone to yank me one and bail me out of what was a big mess. The VK community really never works that way at all. Many nice folks have helped me here and I have done the same in return. One or two did look and theirs were no good. These chassis were around the better part of 10 years! Somebody has a bunch. Maybe not here, or looking at that time.

Even so, RCA or Zenith? I still would say Zenith. Everyone seems to have an RCA because they are talking about repairing them. Less is mentioned about Zenith because quite often they are in the corner playing. No crappy PC boards to deal with and MUCH better flybacks with Zenith. So I wouldn't let one little coil stop me from owning one. We VKers need to put this coil thing to a think tank and come up with a solution! It can't be that hard...
__________________
"Face piles of trials with smiles, for it riles them to believe that you perceive the web they weave, and keep on thinking free"
Reply With Quote
  #7  
Old 06-04-2015, 07:15 AM
zeno's Avatar
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 4,672
Better picture is a matter of taste mostly.
Better built Zenith for sure. No dried up PCB's to deal
with. Hoz eff coil can be dealt with, its mostly a matter
of fit.

73 Zeno
Reply With Quote
  #8  
Old 06-04-2015, 08:26 AM
iong iong is offline
VideoKarma Member
 
Join Date: Apr 2014
Posts: 102
Rca or zenith

Thanks for all the replies. I only have room for two roundies and one I'm keeping is the ctc-5 table top. I was afraid the 29jc20 first Zenith color would not have as nice a picture as other Zenith roundies but if it's hard to tell I would like to keep this one. It's also SC400 (tuner motor gets power but doesn't work) It's the Cambridge 6035. I wondered about flyback life because the high voltage cage has no ventilation. All the later chassis do.
Perry
Reply With Quote
  #9  
Old 06-04-2015, 09:39 AM
Kamakiri's Avatar
Kamakiri Kamakiri is offline
Administrator
 
Join Date: Jun 2002
Location: Buffalo, New York
Posts: 5,109
Every time I work on tube color sets I get dead-ended by something that's impossible for *me* to sort out, therefore by and large I stopped working on them.

They just sit here and look pretty
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia."
Reply With Quote
  #10  
Old 06-04-2015, 10:01 AM
bigaudioal's Avatar
bigaudioal bigaudioal is offline
VideoKarma Member
 
Join Date: Mar 2012
Location: Gaithersburg, MD
Posts: 617
Quote:
Originally Posted by Kamakiri View Post
Every time I work on tube color sets I get dead-ended by something that's impossible for *me* to sort out, therefore by and large I stopped working on them.

They just sit here and look pretty
OH MAN! That does not boost my confidence in working on my first color roundie later this summer/fall. CTC-5 Arliss.
__________________
-Al
Reply With Quote
Audiokarma
  #11  
Old 06-04-2015, 02:37 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 14,762
Quote:
Originally Posted by Tubejunke View Post
We VKers need to put this coil thing to a think tank and come up with a solution! It can't be that hard...
Those efficiency coils and a number of other Zenith coils used the same plastic form....The best solution would be to get an intact original plastic form get it 3D scanned and 3D print a few dozen (or do a mold and cast process). With new forms most old coils could be rewound by hand with reasonable patience.
__________________
Tom C.

Zenith: The quality stays in EVEN after the name falls off!
What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
Reply With Quote
  #12  
Old 06-04-2015, 06:19 PM
Zenith6S321's Avatar
Zenith6S321 Zenith6S321 is offline
VideoKarma Member
 
Join Date: Aug 2010
Location: Charleston, West Virginia
Posts: 303
I have a 1955 RCA 21CT55 and a 1963 Zenith 29JC20 restored and both produce good color pictures. Here are links to the restoration threads with pictures of the results:

RCA 21CT55
http://videokarma.org/showthread.php...=21ct55&page=5

Zenith 29JC20
http://videokarma.org/showthread.php...=29jc20&page=7

The RCA 21CT55 has wideband color demodulation so you can see finer detail in the color. Its early CRT has dimmer phosphors but really nice colors. The fine tuning has to be adjusted carefully to minimize color and sound IF interference visible in the picture.

The Zenith has the 21FJP22A with rare earth phosphors that are brighter and good color, but I prefer the 21CT55 color. The Zenith has the narrow band demodulation so its has a softer color picture than the RCA. The fine tuning is much more forgiving than the 21CT55.

I like both of them very much. I tend to watch the Zenith more, mainly because I feel it does not push its components (such as the flyback) as hard as the RCA. I have installed low speed cooling fans on both sets flybacks, just in case. The Zenith flyback runs cooler than the RCA.

Dave

Last edited by Zenith6S321; 06-04-2015 at 06:27 PM.
Reply With Quote
  #13  
Old 06-04-2015, 06:32 PM
Jon A.'s Avatar
Jon A. Jon A. is offline
Don't mess with Esther.
 
Join Date: Jun 2013
Location: Canada
Posts: 4,267
Quote:
Originally Posted by zeno View Post
Hoz eff coil can be dealt with, its mostly a matter
of fit.

73 Zeno
I'd like to know how to do that. I never know when it might be needed.

I also need to look up the selenium stinkpot replacement info and write it down.
Reply With Quote
  #14  
Old 06-04-2015, 07:57 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 14,762
When it comes to seleniums there are three ways to go: 1.) Measure current and use ohms law to calculate the resistor. 2.) Know that Silicon diodes have a 0.7V forward drop and divide the selenium drop (often 5V IIRC, but can vary with construction of the selenium in question) by .7 to get the number of series silicon diodes needed to match the forward drop. 3.) Get a 20W resistor decade box or power pot and guess and check the high B+ rail against the schematic with different resistances.
__________________
Tom C.

Zenith: The quality stays in EVEN after the name falls off!
What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
Reply With Quote
  #15  
Old 06-04-2015, 08:54 PM
oldtvman's Avatar
oldtvman oldtvman is offline
Larry Melton (oldtvman)
 
Join Date: Jan 2005
Location: Mishawaka, Indiana
Posts: 772
Rca had better color, but because the Zenith sets were hand wired the components set beneath the vacuum tubes which made them last longer because they weren't setting right next to the tubes getting heat damage.
__________________
[IMG]
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:24 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.