02-21-2022, 06:22 PM
Hi Ralph. First, lets make sure the Eico sig gen is working well. I, myself, use an Eico 324 Signal Generator...
[Image: https://64.media.tumblr.com/a5460038db65...867b95.jpg]
They are great for this kind of work, far more forgiving than the modern transistorized ones. First let's check it on the AM broadcast band. If you have a modern radio with a digital frequency dial, which you know is pretty accurate, this will be very easy, if not, use the analog radio you have which has the most accurate dial. Take a piece of wire about 10 feet long and wrap it around a small cardboard tube leaving about a foot free. Strip the end of this free part. attach the signal line (inner conductor) of the RF OUT cable to this stripped end. If yours is original it should have something like an alligator clip on both this and the braid (outer conductor) of this cable. Now, let's check the accuracy of your signal generator first.
Turn on the sig gen and let it warm up for at least 15 minutes. Set both the audio attenuator and the RF attenuator about halfway. Set the range switch to range B. Tune your radio to a station whose frequency you know down near the low end of the dial, below 700 KC if possible. Now tune the sig gen to that frequency and above and below it, and see how close it is. Do the same up near the high end of the dial, just below 1500 KC. This will allow you to verify if the sig gen is working, and how accurate it is.
Once you determine that it is accurate, set the radio dial for 920 KC. This is exactly double the IF frequency used in the model 60. Now, switch the range on the sig gen to A, and tune it to around 460 KC. Go up and down a little but until you get the strongest signal through the radio. Now you know the signal generator is putting out a sound modulated 460 KC signal, and can then align the IF on your model 60. I generally work my way backwards, feeding the signal into the IF amp tube first and aligning the 2nd IF transformer, then going to the mixer tube, and sending the signal in there to align the first IF transformer. I leave it there, and go back and forth a couple of times to make sure they are both peaked.
I use a good, accurate digital readout radio which covers from the AM broadcast band up through 30 MC to double check frequencies the signal generator is putting out every time when I am doing an alignment. When connecting to the grid cap of a tube I use a 100 mmF condenser in between the signal generator center conductor and the grid cap.
I hope these suggestions are of help. I'll keep an eye out for this thread and do my best to help if I can.
[Image: https://64.media.tumblr.com/a5460038db65...867b95.jpg]
They are great for this kind of work, far more forgiving than the modern transistorized ones. First let's check it on the AM broadcast band. If you have a modern radio with a digital frequency dial, which you know is pretty accurate, this will be very easy, if not, use the analog radio you have which has the most accurate dial. Take a piece of wire about 10 feet long and wrap it around a small cardboard tube leaving about a foot free. Strip the end of this free part. attach the signal line (inner conductor) of the RF OUT cable to this stripped end. If yours is original it should have something like an alligator clip on both this and the braid (outer conductor) of this cable. Now, let's check the accuracy of your signal generator first.
Turn on the sig gen and let it warm up for at least 15 minutes. Set both the audio attenuator and the RF attenuator about halfway. Set the range switch to range B. Tune your radio to a station whose frequency you know down near the low end of the dial, below 700 KC if possible. Now tune the sig gen to that frequency and above and below it, and see how close it is. Do the same up near the high end of the dial, just below 1500 KC. This will allow you to verify if the sig gen is working, and how accurate it is.
Once you determine that it is accurate, set the radio dial for 920 KC. This is exactly double the IF frequency used in the model 60. Now, switch the range on the sig gen to A, and tune it to around 460 KC. Go up and down a little but until you get the strongest signal through the radio. Now you know the signal generator is putting out a sound modulated 460 KC signal, and can then align the IF on your model 60. I generally work my way backwards, feeding the signal into the IF amp tube first and aligning the 2nd IF transformer, then going to the mixer tube, and sending the signal in there to align the first IF transformer. I leave it there, and go back and forth a couple of times to make sure they are both peaked.
I use a good, accurate digital readout radio which covers from the AM broadcast band up through 30 MC to double check frequencies the signal generator is putting out every time when I am doing an alignment. When connecting to the grid cap of a tube I use a 100 mmF condenser in between the signal generator center conductor and the grid cap.
I hope these suggestions are of help. I'll keep an eye out for this thread and do my best to help if I can.
