02-24-2022, 10:25 PM
OK, first connect up the signal generator to put out just an AUDIO signal, cable connected to the AUDIO OUT Jack. Turn it on. put a .1 MFD cap on the center lead of the cable, and ground the braid to the radio chassis. touch the other end of the cap to the plate terminal of the #75 tube socket (pin 2). With the radio on and warm, this should inject an audio signal into the circuit at that point. This will let you check the #42 tube and audio output circuits. You should hear the audio tone from the signal generator.
Next touch this end of the cap to the cap of the #75 tube. Again you should hear the tone.
Now switch the probe connection to the RF out. Set the sig gen to 460KC with AF modulation. Change the cap on the output of the probe to a .001 MFD. Leave the shield connected to chassis.
Connect the other end of the .001 cap to the plate terminal of the #78 tube (pin 2). You should hear the tone. Adjust cap #26 until tone is at its loudest. This sets the 2nd IF transformer.
Next switch the capacitor connection to the plate of the 6A7 tube (pin 2). Adjust capacitors #18 and #16 for the loudest tone output. This should align your IF.
I find the Rider's information actually better for aligning these receivers, so here is a link to those pages on Nostalgia Air. This is a pretty good scan, and you should find the information it gives on alignment useful, so read all the pages.
http://www.nostalgiaair.org/PagesByModel...013793.pdf
Next touch this end of the cap to the cap of the #75 tube. Again you should hear the tone.
Now switch the probe connection to the RF out. Set the sig gen to 460KC with AF modulation. Change the cap on the output of the probe to a .001 MFD. Leave the shield connected to chassis.
Connect the other end of the .001 cap to the plate terminal of the #78 tube (pin 2). You should hear the tone. Adjust cap #26 until tone is at its loudest. This sets the 2nd IF transformer.
Next switch the capacitor connection to the plate of the 6A7 tube (pin 2). Adjust capacitors #18 and #16 for the loudest tone output. This should align your IF.
I find the Rider's information actually better for aligning these receivers, so here is a link to those pages on Nostalgia Air. This is a pretty good scan, and you should find the information it gives on alignment useful, so read all the pages.
http://www.nostalgiaair.org/PagesByModel...013793.pdf