02-03-2013, 11:46 AM
Yes, that is what I meant by 2 switches. One just runs the lights.
No, leave the modulation on. I was just saying that it is more of a matter of convenience riding on the RF signal which is what you are looking (listening) for. What I was responding to was when you said this:
"Not understanding how a signal (a tone AF) which I believe is going into that section is going to somehow alter the tuning of the radio"
If the circuit is working like an FM discriminator, deviation (modulation) would be required to see a voltage. So turn up the mod on your sig gen to 100% and hit it with a level high enough that no static or distortion is heard (like quieting the RX on an FM set). That AVC tube has a grunded plate. The dirrections state that you must be centered on freq for this step to work.
At this point I wonder how wide a signal your generator needs to output to see this, 5 kHz (?). Also, Check the instructions, but the IF bandwidth should be set to normal (narrow) while you make this adjustment.
My test for this function is just a bit backwards from the directions. I find a station, not strong or real weak, set the tuning with the "tone" IF narrow, mag tuning off. Then I tune off freq slightly till it is noticable. Then turn the mag tuning on and see if the station comes in better.
Did you check the 2 1M resistors on the grid, 56 and 59? And that 110mmf cap 57 on the 6J5 AVC?
How well did the radio respond on the tuning steps up to this point?
No, leave the modulation on. I was just saying that it is more of a matter of convenience riding on the RF signal which is what you are looking (listening) for. What I was responding to was when you said this:
"Not understanding how a signal (a tone AF) which I believe is going into that section is going to somehow alter the tuning of the radio"
If the circuit is working like an FM discriminator, deviation (modulation) would be required to see a voltage. So turn up the mod on your sig gen to 100% and hit it with a level high enough that no static or distortion is heard (like quieting the RX on an FM set). That AVC tube has a grunded plate. The dirrections state that you must be centered on freq for this step to work.
At this point I wonder how wide a signal your generator needs to output to see this, 5 kHz (?). Also, Check the instructions, but the IF bandwidth should be set to normal (narrow) while you make this adjustment.
My test for this function is just a bit backwards from the directions. I find a station, not strong or real weak, set the tuning with the "tone" IF narrow, mag tuning off. Then I tune off freq slightly till it is noticable. Then turn the mag tuning on and see if the station comes in better.
Did you check the 2 1M resistors on the grid, 56 and 59? And that 110mmf cap 57 on the 6J5 AVC?
How well did the radio respond on the tuning steps up to this point?
