03-29-2018, 08:31 PM
Hi, All:
OK. Don't put DeOxit on rotary switches. I bet you guys all knew that already. I found out accidentally. I decided to let the tuning problem rest and work on something else. One of my dial lights was intermittent, and it didn't seem to be the socket, so I opened up the RF and sprayed some contact cleaner on the switch (which I had put DeOxit on a few days ago while doing the recap.) Well, the light worked better, and so did the radio. So I got some flux remover and scrubbed the whole switch with a soft round brush and rinsed it with contact cleaner. Radio tuned up fine and is playing well. Short wave sensitivity leaves a little to be desired, but it picks up quite a bit of stuff on my long wire, so I'm calling it good. There is a horrific tuning procedure in the Philco service manual involving slapping a separate tuning cap across the oscillator side of the main tuner and then trying to zero beat it with a signal generator or some such. NOT going to happen.
Ron, I'm going to try your idea tomorrow morning. I have to say, it seems too simple, and it is hard for me to imagine Philco would not have done that instead of the stupid bias cell idea.
Many thanks to all who are trying to help. It's coming along!
OK. Don't put DeOxit on rotary switches. I bet you guys all knew that already. I found out accidentally. I decided to let the tuning problem rest and work on something else. One of my dial lights was intermittent, and it didn't seem to be the socket, so I opened up the RF and sprayed some contact cleaner on the switch (which I had put DeOxit on a few days ago while doing the recap.) Well, the light worked better, and so did the radio. So I got some flux remover and scrubbed the whole switch with a soft round brush and rinsed it with contact cleaner. Radio tuned up fine and is playing well. Short wave sensitivity leaves a little to be desired, but it picks up quite a bit of stuff on my long wire, so I'm calling it good. There is a horrific tuning procedure in the Philco service manual involving slapping a separate tuning cap across the oscillator side of the main tuner and then trying to zero beat it with a signal generator or some such. NOT going to happen.
Ron, I'm going to try your idea tomorrow morning. I have to say, it seems too simple, and it is hard for me to imagine Philco would not have done that instead of the stupid bias cell idea.
Many thanks to all who are trying to help. It's coming along!
