When IF's were manufactured were they produced with the plan of the adjusting trimmer screws being in a certain position at install? This question is prompted by working with a radio where the IF's are far off the needed 455 and you want to get back to somewhere close to begin fine tuning. Better to tighten down, open up or go to somewhere in between?
Thanks.

Generally speaking replacement coils and transformers came already peaked to what the application was. If you have an IF transformer that was diddled by someone else, turn the trimmer all the way down. Back off a turn and a half. This would at least put the trimmer in its mid range.

:When IF's were manufactured were they produced with the plan of the adjusting trimmer screws being in a certain position at install? This question is prompted by working with a radio where the IF's are far off the needed 455 and you want to get back to somewhere close to begin fine tuning. Better to tighten down, open up or go to somewhere in between?
:Thanks.
:
Each L-C can be tuned separately. Disconnect from the circuit. One end (call it bottom) is circuit common. The other end (call it top). Feed into the top from a signal generator through a 47K resistor. Feed out of the top through a second 47K resistor to scope or meter capable of reading 455 Khz. (Or a diode and a DC meter). You can then vary the frequency to see where the LC is tuned, and set the L-C wherever you want. Signal generator should have a fairly high output level, and signal be unmodulated. EdM

::When IF's were manufactured were they produced with the plan of the adjusting trimmer screws being in a certain position at install? This question is prompted by working with a radio where the IF's are far off the needed 455 and you want to get back to somewhere close to begin fine tuning. Better to tighten down, open up or go to somewhere in between?
::Thanks.
::
:Each L-C can be tuned separately. Disconnect from the circuit. One end (call it bottom) is circuit common. The other end (call it top). Feed into the top from a signal generator through a 47K resistor. Feed out of the top through a second 47K resistor to scope or meter capable of reading 455 Khz. (Or a diode and a DC meter). You can then vary the frequency to see where the LC is tuned, and set the L-C wherever you want. Signal generator should have a fairly high output level, and signal be unmodulated. EdM
:

Thanks for the replies gentlemen.
Ed when you say connect top and bottom does this mean connect SG to to primary and other device to secondary? I don't have a scope that will measure frequency but the process sounds interesting. Also could you explaine the diode and DC meter hookup as to how this works?

:::When IF's were manufactured were they produced with the plan of the adjusting trimmer screws being in a certain position at install? This question is prompted by working with a radio where the IF's are far off the needed 455 and you want to get back to somewhere close to begin fine tuning. Better to tighten down, open up or go to somewhere in between?
:::Thanks.
:::
::Each L-C can be tuned separately. Disconnect from the circuit. One end (call it bottom) is circuit common. The other end (call it top). Feed into the top from a signal generator through a 47K resistor. Feed out of the top through a second 47K resistor to scope or meter capable of reading 455 Khz. (Or a diode and a DC meter). You can then vary the frequency to see where the LC is tuned, and set the L-C wherever you want. Signal generator should have a fairly high output level, and signal be unmodulated. EdM
::
:
:Thanks for the replies gentlemen.
:Ed when you say connect top and bottom does this mean connect SG to to primary and other device to secondary? I don't have a scope that will measure frequency but the process sounds interesting. Also could you explaine the diode and DC meter hookup as to how this works?
:
Sorry, I have been out of town. The hookup I desscribed is for each section of the IF transformer, primary being one section, and secondary being the other section. Hook up only one section at a time. If you will e-mail me privately at edmustoe@suddenlink.net, and give me your mailing address, I will mail you diagrams and a a IF / radio frequency to DC converter. Unfortunately I have worked on several radios that have been diddled with. There are other ways to get the IF's close if you have no test equipment. For example, if you live fairly close to a radio station, you can temporarily bridge each section of both transformers with a 10K resistor (4 resistors total), pick up the strong station, and with the dial set where the station should be, tweak for max loudness, take off resistors one at a time, re-tweaking as you go. EdM