Why did others drop out of early color manufacturing?

[Don Lindsly]

Several factors slowed rectangular color tubes.
1. Availability of blanks from Corning
2. Consistency in corner convergence
3. Shutting down round tube production to make way for rectangular tube capacity
4. Availability of thin CRT guns
5. Availability of yokes, flybacks and other components, in production quantity, to support the new format
6. Reluctance of other manufacturers to commit too soon
7. Heat problems in the thin neck. That's one reason most rectangulat tubes run on lower heater current.
8. Getting the service industry up to speed
9. Why push it prematurely if round tube color sets were selling well? Wait until it's ready. The manufacturers did not want to repeat the first generation mistakes that were still fresh in the serviceman's and customer's minds.
10. Don't forget that most round tube sets looked pretty good 35-45 years ago. They were relatively new, had good bright CRTs and nice pictures. Greed was not the prime factor. It was what the public would accept.

Don

[old_tv_nut]

Cutting off the top and bottom probably made convergence easier, but I think it was mainly that porthole designs were long dead, and black and white sets had already gone from cut-off to rectangular - so going to flat top and bottom was only one stylistic step backwards. The RCA 15 inch tube had an internal bezel defining this shape. Thsi disappeared when tube construction was simplified for the 21-inch, but the external bezel was cutoff the same way.