Quote:
Originally Posted by wa2ise
RCA, in the early 80's, was using, in production, a kind of magnetic tape that was formed in a ring around the CRT neck. In the factory, they would adjust various magnetic fields thru this tape ring, to do convergence. Once the factory worker felt that this convergence was good, on this particular CRT, the production machine making the convergence fields would "record" these magnetic fields into this magnetic tape, like a tape recorder does to imprint the desired magnetic fields onto tape.
Field repairs would require that the TV repairman throw away this piece of tape, and install a thing that had several adjustable magnetic rings, and adjust them to get convergence. repairs like replacing the yoke, or the CRT.
Don't know if RCA was using the above magnetic tape scheme in 1978.
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I've seen it used on most RCA sets that used an in-line CRT from the late '70's until recently. It would have been nice if a delta gun CRT could have been converged that way.
I've never had the need to remove the tape on these CRT's. By the late '80's, RCA CRT's featured bonded yokes which means the whole CRT, yoke, and convergence magnet is changed as a unit. Sure beats having to set the purity and convergence. The downside is that if the yoke fails; you have to change the CRT unless you can figure out how to un-bond the original yoke. Fortunately, I've never seen a bad yoke on the bonded RCA tubes.