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Old 03-11-2016, 09:27 AM
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dtvmcdonald dtvmcdonald is offline
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Join Date: Nov 2012
Posts: 1,266
You are a very lucky man! I don't have to be envious, as I have a very nice one.

I'd love to see pictures of the set's bottom. Those pots on the top have very
long stems and look like they are replacements. That's a good thing, as the
short ones are hard to get to with the chassis in the cabinet.

Note that McVoy convinced me that the very low voltage electrolytic 2C107
(1000 uF 3V NONPOLAR) need not be replaced, and he was right. Leave it be!

Note also that there are production changes in that part of the circuit (around 2C107)
which you need to be aware of.

BEWARE! of the resistor value of 2R242, in the first convergence amp plate. RCA says 270K, Sam's says 27K. 270K simply cannot generate those voltages, verified by my direct measurement. 27K can, and works, but my convergence pot is set at the
absolute top of its range. I suggest 35K.

Good luck with the usually bad white peaking coils. Don't try finding exact replacements. I do not suggest using the "usual suspect" old Miller or Meissner
replacements for the larger value ones but rather modern ferrite core ones. The
6.8 mH one might better be replaced with a smaller one, like 4 mH. If needed I can look
up the part numbers of the ones I finally selected from an assortment of old and modern ones I bought when I restored mine two years ago.

Also ... if you have and are good with a scope, I strongly suggest running the recapped chassis on the bench, and doing sweep generator tests
of all the areas with those nasty coils, before you declare victory over them. Different
coils with the exact same inductance value can generate hugely different responses,
with hugely different picture responses. You can make the Q response quite a bit
flatter than the traces in RCA or Sams, and the picture difference is quite a bit too.

Another tip ... while working on the three color amps (with may of those coils),
check each and every color/luminance matrix resistor and replace any that are
more than 5% off. If you send me a private message I can send you big pile of
test images especially designed for the CTC2 chassis and its matrix.

Finally ... if yours is like mine, I suggest a long chain of 5W 200V Zener diodes in place of 3R260.

As others have, have fun and be fastidious!
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