21CYP22 vs 21CYP22A

[benman94]

I'm just curious as to what exactly is different between the two tube types. I've looked at the datasheets for both tubes but they seem to be identical with the exception of the tube number.
Thanks,
Benny

[N2IXK]

From the RCA 21CYP22-A datasheet:

"The 21CYP22-A offers two major improvements--simplified color-field setup, and improved tube reliability. The tri-color screen of the 21CYP22-A features greater tolerance for "beam-to-dot" register with the result that color fields are set up more easily and the need for adjustable field equalizer magnets is eliminated. Useful cathode emission is prolonged and tube reliability improved by lower temperature operation of the cathodes. Such operation is achieved through the use of improved ceramic-supported cathodes and reduced-current heaters."

[benman94]

Thanks. I only have the Sylvania and GE datasheets in my collection...

[N2IXK]

Comparing the 2 RCA datasheets shows that the heater current was dropped from 1.8A to 1.6A at 6.3Vac.

[zenithfan1]

Nice to know! I didn't have a clue of the difference until now, I just knew something was different from the non-A. Looks like they made the right changes to it. The one in my 7 is an "A" version, installed in 1965. It has lotsa life in it, infinite life test. It might as well be NOS. I'm glad as it is the only set that I have with a CYP, my 9 has the sulfide FBP installed 4-68.