01-05-2022, 12:56 PM
Yes, now you are making some progress. Next you will have to monitor the AFC voltage at the kill switch.
With the primary of the discriminator now tuned and strong received signal you should see some voltage at the kill switch. This voltage should change from plus to minus to zero depending on the setting of 85B. As you slowly turn 85B in one direction, the voltage should change from near zero to a positive peak, then drop through zero to a negative peak and then return to near zero. You want to set 85B to the zero point between the plus and minus peaks.
This is the typical "S" curve of a discriminator. See page 26 of Rider's chapter on the discriminator and what the proper tuning curve plot looks like.
If you still see no AFC voltage at the kill switch, check for shorts on the AFC control wires or a bad 6H6. There is not much else in the circuit except for a few resistors and caps in the 6H6 cathode circuit to cause problems.
With the primary of the discriminator now tuned and strong received signal you should see some voltage at the kill switch. This voltage should change from plus to minus to zero depending on the setting of 85B. As you slowly turn 85B in one direction, the voltage should change from near zero to a positive peak, then drop through zero to a negative peak and then return to near zero. You want to set 85B to the zero point between the plus and minus peaks.
This is the typical "S" curve of a discriminator. See page 26 of Rider's chapter on the discriminator and what the proper tuning curve plot looks like.
If you still see no AFC voltage at the kill switch, check for shorts on the AFC control wires or a bad 6H6. There is not much else in the circuit except for a few resistors and caps in the 6H6 cathode circuit to cause problems.
