09-08-2023, 06:59 PM
Since you seems to have removed the resonant tank caps (else why would you ask about their values; micas are rarely need replacement, and in 50-s radios they are rarely subject to the SMD), unless they were destroyed, just measure them wigth a good C-meter (not with a DMM, they are not accurate in the units of pF, though you could try to press "delta" if it is a Fluke) and see if they are good.
In case the caps are bad (destroyed, broken during removal etc):
1. If the coils are good, measure L at the frequency as close to the IF as possible (my Stanford allows 100kHz which is better than 1kHz or 10kHz). Leave the slug in the position it was originally of not disturbed. If it was out, put it more or less in the middle before the measurement.
2. If the coils are bad, rewind as close as possible to the original. Then do the measurement.
3. When knowing your L, calculate the C from the standard tank formula (1/(6.28 * sqrt(L*C)))
4. Find a mica cap closest to the calculated value, then solder it in and using the generator, measure the resonant frequency (either by observing the V or I), see if you could put it in 455kHz moving the slug.
If the frequency is out of range, change the capacitance.
5. Do that for the second coil.
In case the caps are bad (destroyed, broken during removal etc):
1. If the coils are good, measure L at the frequency as close to the IF as possible (my Stanford allows 100kHz which is better than 1kHz or 10kHz). Leave the slug in the position it was originally of not disturbed. If it was out, put it more or less in the middle before the measurement.
2. If the coils are bad, rewind as close as possible to the original. Then do the measurement.
3. When knowing your L, calculate the C from the standard tank formula (1/(6.28 * sqrt(L*C)))
4. Find a mica cap closest to the calculated value, then solder it in and using the generator, measure the resonant frequency (either by observing the V or I), see if you could put it in 455kHz moving the slug.
If the frequency is out of range, change the capacitance.
5. Do that for the second coil.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.