View Full Version : Zenith Chromacolor tubes...--why are they so much BETTER?


rca2000
05-02-2016, 06:20 PM
Just WHAT did Zenith do--to make the CC CRT's SO great?

Over the weekend..at the ETF while watching a CRT being rebulit for the FIRST time there...I asked Jerome Halpren (sp) about what it was that made Trinitron tubes un-rejuvinatable. he said the cathode coating is VERY thin to begin with and so...there is just NOTHING to "uncover" when trying to bring one back, and also...he suspected the very close spacing of the single-gun design to the the cathodes would NOT allow restoring current to properly flow...and so nothing can be "restored". Makes sense to me..

On the OTHER hand...something i FORGOT to ask...was about the Zenith Chromacolor delta tubes. I wanted to know what is DIFFERENT about them...that makes them so much BETTER..it seems...than almost ANY other tube.. to last so long and STILL look SO good...after all of these years.

I suspect it is the OPPOSITE situation to Sony...likely real thick coating on the cathode which just does NOT wear out very fast. Does anyone know if this is right--or is it something else?

TUD1
05-02-2016, 06:50 PM
The tube in my new 1973 Chomacolor solid state set still tests strong. I suspect that it was used from 1973 to 1985, then the owner bought a new Zenith. 12 years of good use and it still checks good. How was the ETF? I wanted to go but I have no $$$.

rca2000
05-02-2016, 07:21 PM
I would have to say...for ME at least...it was THE most productive one--since the beginning one--in 2003 !!

I did good selling in the auction AND ALSO...brought home a REAL prize...a Philco 48-700 tv, a set I have wanted for MANY years...but they ALWAYS seem to "get away" from me-- This one did NOT do so...and it has been RESTORED , some time ago too !! This set is like a Pre-war set--with it's "line powered HV supply" (AKA "Brute force HV supply") !!

Along with that...I filled the van with stuff form the silent auction and a coupe of sets brought to me by others..


In total...I brought back:

The Philco 48-700 set.
A sylvania cold 23" BW tube set (from a collector in wisconsin, got a ride here )
A Sears cold table model metal color 19 or so inch tube set (brought in return for my picking up a CRT for a member here )
An RCA "tin can" cold set ( my 3rd one..)
A Philco 1957 or so cold BW tube console
A Conar 19" Metal cold BW set--in GREAT physical shape..

I had to leave a Zenith CC SS console there--no room--I will return and pick it up soon.


SO all told...a GREAT haul!! and ALSO nice...to have "been there" to witness the birth of a ""new" CRT, at the rebuild shop. (Status of it is still unknown, as there was no actual way to "set test" it at the time).

DavGoodlin
05-04-2016, 12:58 PM
I have to add my own Zenith CRT miracle: A 25V tube in a chassis 25DC57 console (1973 chromacolor I) was weak on blue and short on vertical when picked up in 1985. We delivered them a new Panasonic IIRC and the old Zenith "fell out of the van" at my house:D somehow.
After working on the 24v supply regulator, recapping the vertical module and changing the 22-5001 HV hold-own caps...I put the Heathkit CRT tester on it and was very discouraged by emission, life and cutoff tests. I figured WTF so I gave it the cleaning (ac current between K-G1), not much better:sigh:, then I decided to rejuvenate (250V DC electrolysis K-G1 with current limiting lamps) and watched the needles climb.

The set lasted another 15 years!!!!! Then my folks got a Sony 27FS something. The set relocated to my garage for continued use but I parted it out a few years later after multiple issues surfaced due to the humidity-cold cycles there, I regret doing that.
I still have the CRT and chassis today.

radiotvnut
05-05-2016, 01:24 AM
I had a similar experience with an early E-line upright chassis CCII with "instant on." Someone brought it in to the electronics class at the local community college and the tube was so dead that the screen would barely light in a darkened room. My instructor said that if they didn't want it back, I could have it. I offered to try the rejuvenator on it; but, he didn't want to bother with it. He told them the picture tube was bad and they said I could have the set. I brought it home, threw my B&K 470 on it, and all 3 guns were dead. I rejuvenated it and all 3 guns came up and the set produced a nice picture. I sold it to someone and never saw it again.

Over the years, I've seen a lot of Zenith TV's with delta gun CRT's and that's the only one that's ever tested that bad. I've had a few that were tired; but, still made a very watchable picture.

It's sad that a company that once produced the best tubes in the business ended up producing the worst tubes ever made.

sampson159
05-05-2016, 09:04 AM
saw many zenith delta gun crts.never saw one that didnt produce a decent picture except for the one in a vertical chassis combo that was given to me.the worst one but it still has a watchable picture,with good brightness and contrast but a very soft focus.it s sitting behind another combo so the chances of me getting to it are pretty slim right now.will eventually give it a jolt and see what happens.also the zenith and some rca crts weigh approx 12 lbs more than other crts.

Captainclock
06-08-2016, 05:19 PM
saw many zenith delta gun crts.never saw one that didnt produce a decent picture except for the one in a vertical chassis combo that was given to me.the worst one but it still has a watchable picture,with good brightness and contrast but a very soft focus.it s sitting behind another combo so the chances of me getting to it are pretty slim right now.will eventually give it a jolt and see what happens.also the zenith and some rca crts weigh approx 12 lbs more than other crts.

Yeah but I bet your Zenith Chromacolor picture tubes probably don't weigh nearly as much as a Sony Trinitron picture tube... :scratch2:

sampson159
06-09-2016, 10:51 AM
but the zenith tubes are still around producing sharp pictures after 40 plus years.not a sony fan but have had a few that had fine crts.always wondered why those zenith and rca tubes weighed more?