RCA 21CT55 #8802897 is Dead

[Electronic M]

Originally Posted by dtvmcdonald

Tom: The "one resistor" means one less. A couple of values in the matrix are different. I doubt you will be able to see a difference. Only the relative noise in the colors and the (small) spurious color line caused by the different demod axes
will be different.

The difference you will see will be determined almost
entirely by differences between the types of peaking coils used
to replace the nasty white ones that self-corrode. That makes huge differences.
I spent hours and hours getting the right coils to get the sharpest and least ringy color bars. I tried a couple of the ones specified as replacements in the manual, and they were disastrously wrong.

I just use the peaking coils off digikey that Nick Miniman82 recommended many years ago. Such as this (this is one of several from that list): https://www.digikey.com/en/products/...-223-rc/969835

I've heard those coils criticized by more than one person, but the people doing the criticism don't site modern off the shelf parts as being part of their better solution...I don't have time to hunt out of production borderline unobtainium, I also don't have the equipment or skills to rewind much less wind new multi-layer coils or properly characterize them or verify performance outside of eyeballing the screen (I also don't have money or time to pick that up)...So until someone comes up with a better list of current production off the shelf parts I can buy off mouser or digikey I'm going to stick with what I know works decently in both of my sets and very soon a set I'm restoring for a customer.