I (Beginner)am in the process of aligning a RCA C13-2 (1934)receiver. When aligning the IF stages I find that one trimmer screw is very sensitive (able to tune to a peak audio signal from Signal Generator in a very narrow range) signal will go away if screw turned to far). Turning the other trimmer screw will keep producing a signal even after many turns and making it very hard to find the peak. Is this a natural heppening or do I have other problems that I need to look at? After I aligned it best that I could, stations were received across the dial range but a local station was much weaker than it was before. Before I aligned it a local station was loud (1340KHz)but stations at other end of scale could not be heard. I hope this is enough information to go on. Thanks for your help.

: I (Beginner)am in the process of aligning a RCA C13-2 (1934)receiver. When aligning the IF stages I find that one trimmer screw is very sensitive (able to tune to a peak audio signal from Signal Generator in a very narrow range) signal will go away if screw turned to far). Turning the other trimmer screw will keep producing a signal even after many turns and making it very hard to find the peak. Is this a natural heppening or do I have other problems that I need to look at? After I aligned it best that I could, stations were received across the dial range but a local station was much weaker than it was before. Before I aligned it a local station was loud (1340KHz)but stations at other end of scale could not be heard. I hope this is enough information to go on. Thanks for your help.

Hi
The different reaction to IF transformer adjustments is normal.

Before aligning the IF transformers, I would align the RF and oscillator adjustments. You have a good 13 tube radio so you probably have a 3 section tuner. Each band should have its own set of trimmer caps. You should adjust these trimmers on the high end of each band. Your station at 1340 will work. Set your dial pointer to where the station should be. Adjust the oscillator trimmer so the station lines up with the pointer. The oscillator trimmer adjustment is the one that moves the stations. Then adjust the other two broadcast band trimmers for the loudest signal. You can use the "eye" tube as an indicator if you would like. Now the low end of the dial might be weak. The radio should have a padder. It will look like a trimmer, only be larger. Adjusting this will handle the low end of the band. I would first tune in a station near the low end. Adjust this padder while moving the dial back and forth. The padder will move the stations but you will find at one spot they are the loudest. After you have the RF section aligned then peak up the IF's for max volume. The "eye" tube, if it is working, is a great indicator for adjustments. Good luck.
Norm

: : I (Beginner)am in the process of aligning a RCA C13-2 (1934)receiver. When aligning the IF stages I find that one trimmer screw is very sensitive (able to tune to a peak audio signal from Signal Generator in a very narrow range) signal will go away if screw turned to far). Turning the other trimmer screw will keep producing a signal even after many turns and making it very hard to find the peak. Is this a natural heppening or do I have other problems that I need to look at? After I aligned it best that I could, stations were received across the dial range but a local station was much weaker than it was before. Before I aligned it a local station was loud (1340KHz)but stations at other end of scale could not be heard. I hope this is enough information to go on. Thanks for your help.

: Hi
: The different reaction to IF transformer adjustments is normal.

: Before aligning the IF transformers, I would align the RF and oscillator adjustments. You have a good 13 tube radio so you probably have a 3 section tuner. Each band should have its own set of trimmer caps. You should adjust these trimmers on the high end of each band. Your station at 1340 will work. Set your dial pointer to where the station should be. Adjust the oscillator trimmer so the station lines up with the pointer. The oscillator trimmer adjustment is the one that moves the stations. Then adjust the other two broadcast band trimmers for the loudest signal. You can use the "eye" tube as an indicator if you would like. Now the low end of the dial might be weak. The radio should have a padder. It will look like a trimmer, only be larger. Adjusting this will handle the low end of the band. I would first tune in a station near the low end. Adjust this padder while moving the dial back and forth. The padder will move the stations but you will find at one spot they are the loudest. After you have the RF section aligned then peak up the IF's for max volume. The "eye" tube, if it is working, is a great indicator for adjustments. Good luck.
: Norm

The general allignment procedure that I learned is : 1) using a signal generator or a modulated crystal oscolator on the IF frequency tune the last IF transformer (nearest the detector) first and work towards the mixer.
2) Adjust the high end of the band by setting the main tuning dial to a high end station or pree chosen signal generator frequency and adjust the oscolator coil, series trimmer capacitator and paralel padder capacitator. Repeat without disturbing the coil at the low end of the band alternating band ends until the dial agrees with the stations recieved..
3) finally touch up the tuning of the antenna coil(s) and trimmer(s) working towards the antenna.

It seems to me that we could makea pretty good signal generator from a couple of ICs and three crystals (a 455khz or 456khz or 1600khz for IF stages a 550 or 600 khz for the low end ofthe band a1450 or 1500khz for the high end of the band) a 7400 series IC 4 capacitators and 6 resistors to make a DEDAH oscolator and a 1 of 4 selector IC to act as the inverter stage of the crystal oscolator. the crystals are connected between 1,2,and 3 inputs and the inverting outputs of the selector IC . The output of the DEDAH oscolator are fed through switches to the selector inputs of the selector IC choosing which crystal is in the oscolator circuit.
Theoretically I think this should work.