Hello all!
I am still working on a GE 501 chassis. This evening I was looking at the schematic and discovered what I think is a wiring problem with the 35w4 rectifier tube. According to the schematic there is no connections on pins 1 and 2. There is a 22 ohm resistor, a filter capacitor, c23a, and the red lead from the audio transformer. In the chassis there is a 22 ohm resistor, a filter capacitor, and the red lead from the audio transformer but these are all connected to pin 6(center tap used for an indicator lamp).
In the chassis there is also a 1000 ohm resistor connected to the cathode(pin 7) the other end is connected to +90 volts. I failed to tell you the other end of the 22 ohm resistor is connected to pin 1 of the 35w4. Any ideas if this is correct wiring?
When I insert a 455khz signal at the input of the 12sa7, I get good volume at the speaker, there is no stations, however.
I am very greatful for any help!!!
Thank you!!
Daniel

If you have about +90v on the B+ line.... and you get a good audio tone when you inject a modulated 455khz sig at the mixer stage.... then ... for the most part the radio is basically operating ... at least s far as the IFs go and the audio section.
So check to see that the antenna is properly connected and there are no shorts in the tuner capacitor.
Also make sure the local oscillator is running.

You can place a good working radio next to this one and set it to about 1400khz.... then tune the radio under test to around 1000khz. If the local osc is running you should hear squealing hetrodyning in the good radio.

Based on your description, the rectifier tube and its associated parts are miswired. It is unclear why this was done, but it seems pointless and the set should be restored to its factory wiring configuration as indicated on the schematic.

The upshot of the change appears to be that a 22 ohm series resistor in the B+ line was replaced with a 1000 ohm resistor, and a B+ filter capacitor was eliminated altogether. This may have been done because the previous owner didn't have a replacement electrolytic capacitor... but who knows? If the circuit is as you have described it, it will not provide adequate B+ current and there will be considerable AC hum.

Would seem if the audio is loud and there is no hum that the power supply may be working properly.

Clifton

:Based on your description, the rectifier tube and its associated parts are miswired. It is unclear why this was done, but it seems pointless and the set should be restored to its factory wiring configuration as indicated on the schematic.
:
:The upshot of the change appears to be that a 22 ohm series resistor in the B+ line was replaced with a 1000 ohm resistor, and a B+ filter capacitor was eliminated altogether. This may have been done because the previous owner didn't have a replacement electrolytic capacitor... but who knows? If the circuit is as you have described it, it will not provide adequate B+ current and there will be considerable AC hum.
:
:
:

Hum may be difficult to assess if he can only get a 400 Hz audio tone through the set using a signal gen...and it's also possible that there are additional components/connections present that aren't fully or accurately described.

If he has good volume and there is no loud hum, then the power supply, audio and output amp may be working ok.

Clifton

:Hum may be difficult to assess if he can only get a 400 Hz audio tone through the set using a signal gen...and it's also possible that there are additional components/connections present that aren't fully or accurately described.
:
:
: