Quote:
Originally Posted by Ralph S
Penthode: I was very careful to measure the capacitance of the IF coupling caps that I removed and found them to be within 1 or two pfs of what the schematic called for. I replaced them with silver micas that were also within that same spec. The IF and set performance seems to be exactly the same as it was before this change. The audio is good since it was not touched and it lines up exactly with the video which was changed. I'm easily getting clean video through 4 megahertz; so I doubt it needs a realignment at this point. Why that gentleman advised Phil to change them, I don't know. I agree about RCA's micas being pretty reliable.
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Ralph, I appreciate the care you have taken. I just would like to point out the RF/IF sections are critical. Changing the micas in the IF strip is generally not required. One has to be cautious when changing parts, especially when it affects tuning in these areas.
Even though you have taken the care to ensure the same capacity, tuning will have drifted and the set would generally benefit from an alignment check.
I have try to convey the need for systematic restoration and troubleshooting, especially to beginners, otherwise things can get out of hand.
Saying that, I am happy for your success and congratulations getting the set working again.