I see the antenna aerial transformer schematic - I’m reading pins 1 through 4 counterclockwise with a cap connected to 1, pin 2 connected to the chassis, pin 3 connected to 7C6, and a wire going from the tuning condenser to the 7A8, and the antenna leads going to pins 1 and 2 on the coil. Also a wire underneath the tuning cap going to the oscillator transformer.
I think I have this totally confused - does anyone have a good picture showing where the antenna leads etc go?
After attaching an outside antenna and checking the connections against the schematic -and realizing two were reversed - I now get loud volume and a rushing noise - no stations.. As the only tube I haven’t replaced with a known good tube is the 7C6 detector - I’m thinking that might be the problem. New one on order.
(This post was last modified: 5 hours ago by bridkarl.)
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desired outcome. One end of the loop antenna is connected to the tuning condenser and pin 6 7A8. The other end of the loop antenna is connected to pin 3 of the antenna transformer. Pin 4 of the antenna transformer is connected to the AVC wherever it comes from. Pin 1 of the antenna transformer is connected to a long wire antenna, which you probably won't need right now. Or you can just connect a short one. Pin 2 of the antenna transformer should have the 0.0015mfd capacitor connected then the other end of the capacitor to ground.
If you get the same results then this is a symptom of the local oscillator not working. If you have a signal generator, feed a modulated rf signal at the IF frequency to pin 6 of the 7A8 through a 0.047mfd cap. If you get a tone at the speaker then the oscillator isn't working.
You stated you connected pin 3 of the antenna transformer to the 7C6. There is no such connection on the schematic.
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So the wire is there connected wrong at the transformer - which would be one problem. As I look at the original picture I took the blue wire from 7C6 it seems to go to a pin - pin 2??
I think my confusion here is not understanding the numbering sequence. I’m reading the pins - looking from the side of chassis towards the tubes as 1 being on the top left and going clockwise. With the cap in the photo attached at 1. I’m not interpreting the diagram on the schematic with the pin numbers correctly I think. Pins 1 and 2 could be 180 degrees opposite.
I’ll draw myself a pic based on your answer and see if I can visualize the schematic better. Thanks.
(This post was last modified: 38 minutes ago by bridkarl.)