My wife dragged it home from a garage sale in 1996 for $35. I fixed the remote and got a picture with no ant. Since I had no interest in TVs at the time it just sat disconnected in my office collecting dust. I finally fired it up on a test DVE disc thru a modulator a couple of days ago and got a bright, fine detailed picture with accurate color and near perfect focus! Well that got me interested in learning more about it.

Its a 25in Zenith System 3 made in Springfield, Missouri in April 1986. The CRT is A63AAX02X with a backward cap R sticker which makes it Japanese, right? The screen is stripped like my Sony Trinitron and probably has inline guns. When I took the back off, the CRT has NO convergence assembly like the Sony, just three purity rings stacked together! The yoke has only the usual 4 wires, so no dynamic convergence in here.? The ultor is a single conductor, so no electrodynamic convergence like the Sony Trinitron. I thought the Trinitron was hard to understand but this Zenith thing is spooky!

The plug in assemblies are noted as follows:
Video output 9-467-01
Main module 9-518
SM pwr supply 9-520-02
Tuner 175-2277-01

So what do the Zenith Gurus make of this. Its got 10yrs of main TV use, then retired for 13yrs and still produces a picture as good as any of my analog TVs with the obvious exception of the Sony PVM1334 super-fine pitch pro monitor.

Photos presented in last page of AudioKarma, Early Color Television :
"I've been blessed! #139" http://www.audiokarma.org/forums/showthread.php?t=124126&page=10

000

Many sets using inline tubes have the yoke and convergence magnets bonded to the CRT where no adjustment can by made. When you change the tube, you change yoke and all. Most all of the Thomson era RCA's are like this.

I like these too. Not the best of the time (I like Mitsubishis from the late 80s), but they usually look good.

Thanks for the info regarding the "modern" in line CRT in my 1986 Zenith. I realize I'm about 30yrs behind the CRT technology curve. I still don't have a theoretical understanding of how the Trinitron works let alone the self-conversion yokes that possibly all current CRT TVs employ. Fink's "Television Engineering Handbook", First Edition of 1957 is my only professional reference source when I lost interest in TV as a hobby in about 1966. Now that I'm back into the hobby, I'll have to get the latest edition of Fink or its equivalent.....Tom

000

It seems the self-conversion yokes of the '80 and later is well described and understood by some of the the present AK members. Apparently their knowledge is sufficient for them to properly converge all inline gun CRTs with their stripped phosphor screens. How was this practical knowledge acquired without a complete theoretic understanding of each application's self-conversion yoke operation? Surely it was not obtained soley from Sam's terse step by step alignment procedure.

There must be an engineering level book out there that covers the modern inline, striped screen CRTs employing full two axis conversion entirely contained in the single yoke assembly. This treatment must be to the level of the original Fink "TV Engineering Handbook" description of the delta gun, screen and deflection system of the 21AXP22. If any member knows the existence of such a book or extended technical paper, I would greatly appreciate they reveal this to me as a message on this thread or private message. Thanks for your continued interest in my CTV education.....Tom

There must be an engineering level book out there that covers the modern inline, striped screen CRTs employing full two axis conversion entirely contained in the single yoke assembly. This treatment must be to the level of the original Fink "TV Engineering Handbook" description of the delta gun, screen and deflection system of the 21AXP22. If any member knows the existence of such a book or extended technical paper, I would greatly appreciate they reveal this to me as a message on this thread .....Tom

Hitachi sure has a convoluted alignment method for some of their CRT sets - attached is an excerpt of one.

Cheers,

Brian, thanks for the self-convergence yoke CRT info. I guess a competent service tech could replace a CRT using all the original neck hardware but what a frustrating and expensive job that would be. No wonder most (all) current replacement CRTs come from the factory with yoke and all other setup components epoxied to the envelope. Has anyone here ever installed a bare CRT-only? The document was useful to me since it demonstrated that current CRT theory and implementation knowledge is necessary to fully appreciate the almost unbelievable accomplishment of its designers.

I don't know about the other members of this forum, but I am disappointed I must pursue this hobby without a detailed engineering knowledge of how this CRT operates. Surely it is disclosed in some available documentation, or is this prepriority information of each manufacturer? .........Tom