Hello
I have a Zenith 9-S-30 with an open primary in the input transformer. I do not know what the primary is supposed to read because it is not listed on the schematic. The secondary is still good and it is about 1200 ohms overall. I have put in a P-T124D from AES and the volume doesn't seem to be loud enough- primary totals around 500 ohms and secondary totals about 750 ohms. Does any one know which transformer would be a suitable and correct replacement from AES? Any help would be appreciated.
Ryan

Hi Ryan

Your radio should have plenty of volume. It has 2 6C5 audio stages before the push pull output. Check plate voltage on each 6C5 tube, pin #3. Should be positive.

I would normally use P-T156 which has a 1:3 gain but don't think it's needed in your radio. Impedance is important in transformers rather than DC resistance.

Norm

:Hello
:I have a Zenith 9-S-30 with an open primary in the input transformer. I do not know what the primary is supposed to read because it is not listed on the schematic. The secondary is still good and it is about 1200 ohms overall. I have put in a P-T124D from AES and the volume doesn't seem to be loud enough- primary totals around 500 ohms and secondary totals about 750 ohms. Does any one know which transformer would be a suitable and correct replacement from AES? Any help would be appreciated.
:Ryan

Hello Norm
Thanks for the information. The voltage on the schematic indicated 22 and 230 volts on pins 3 of the 6C5 tubes. The voltages exceeded those values. So I began checking the voltages on pin 3 of the other tubes-all fine until I got to the 6A8; read -4 volts. I traced the problem to the primary side of that coil. The winding was tore in two pieces inside the can where mice had frayed and torn the wiring. This radio was basically a "rat den" when I got it. I repaired the wire and the radio is absolutely unbelievable in volume and reception. Thanks again for the tips and help.
Ryan
:Hi Ryan
:
: Your radio should have plenty of volume. It has 2 6C5 audio stages before the push pull output. Check plate voltage on each 6C5 tube, pin #3. Should be positive.
:
: I would normally use P-T156 which has a 1:3 gain but don't think it's needed in your radio. Impedance is important in transformers rather than DC resistance.
:
:Norm
:
::Hello
::I have a Zenith 9-S-30 with an open primary in the input transformer. I do not know what the primary is supposed to read because it is not listed on the schematic. The secondary is still good and it is about 1200 ohms overall. I have put in a P-T124D from AES and the volume doesn't seem to be loud enough- primary totals around 500 ohms and secondary totals about 750 ohms. Does any one know which transformer would be a suitable and correct replacement from AES? Any help would be appreciated.
::Ryan