02-21-2015, 10:31 AM
Is T3 connected correctly?
AM signal is detected at pin 6 of the 19T8. The detected AM audio leaves T3 via the junction of R10 and R11, goes to the band switch, and from there to the volume control.
I am surprised you are getting AM audio at the screen grid (pin 6) of the 12AU6 limiter - unless I am missing something, I don't think you should be.
Or do you mean you are connecting a jumper between pin 6 of the 12AU6 and pin 6 (also screen grid) of the 12BA6 2nd IF? If so...then you have lost screen grid voltage to the 12BA6 2nd IF. You are in effect restoring that SG voltage to the 12BA6 when you connect the jumper.
The R1 in series with the SG of the 2nd IF now becomes suspect, as does C13, .002 uF. Make sure that R1 is not open, and that C13 is not shorted. Your SG should be connected to terminal 1 of T3, also.
Measure voltages, especially at the plate and SG of the 2nd IF tube.
AM signal is detected at pin 6 of the 19T8. The detected AM audio leaves T3 via the junction of R10 and R11, goes to the band switch, and from there to the volume control.
I am surprised you are getting AM audio at the screen grid (pin 6) of the 12AU6 limiter - unless I am missing something, I don't think you should be.
Or do you mean you are connecting a jumper between pin 6 of the 12AU6 and pin 6 (also screen grid) of the 12BA6 2nd IF? If so...then you have lost screen grid voltage to the 12BA6 2nd IF. You are in effect restoring that SG voltage to the 12BA6 when you connect the jumper.
The R1 in series with the SG of the 2nd IF now becomes suspect, as does C13, .002 uF. Make sure that R1 is not open, and that C13 is not shorted. Your SG should be connected to terminal 1 of T3, also.
Measure voltages, especially at the plate and SG of the 2nd IF tube.
--
Ron Ramirez
Ferdinand IN
