1979 GTE Sylvania GT Matic CX9164W chassis E24-3

[radiotvnut]

Those were made from about '75 until '80, when they were replaced by the E32 single-board chassis with an IHVT.

On your set, triplers were a high-failure part, as well as the filter capacitor and bad solder connections. I ran into a few bad yokes and a number of weak tubes on these. When they're right, they have a nice picture. I think the tripler on these is an NTE523A.