01-06-2022, 11:19 AM
Hi guys -
Working on a model 90 Cathedral, middle edition with the single 47 tube.
https://philcoradio.com/library/download...l.%201.pdf
It was a playing set when I started re-building bakelite blocks. Part #28 was rebuilt without issue. While awaiting a resistor order I rebuilt part #47, 3615-E block with a single .05 mfd cap. Replaced the cap and when I reinstalled I get virtually no reception now. This block only has two connecting tabs. Part #45, a 51k ohm resistor measures 58k. The block terminal where this resistor connects also has two white wires. One short wire terminates at the first IF Transformer. This wire was brittle and loosely connected. I replaced it but no change in behavior. Replaced the 24 tube at this IF with no change.
When the volume is turned all the way down I hear a weak reception from our strongest local station. When I turn up the volume all audio drops with an occasional crackle as I work it's range. Only fully turned down does any reception come through, weakly at that. The documentation I have doesn't show the volume pot values as I wanted to verify it was still good. I cross referenced to a few 30's era Philco parts booklets I have but none list its value.
I removed the bakelite block connections and measured the newly installed cap, still a solid .05mfd. I connected my signal generator to the set but could not pick up a signal anywhere. I'm missing a basic troubleshooting step here and looking for assistance on next step to identify what's gone wrong.
Many thanks,
Paul
Working on a model 90 Cathedral, middle edition with the single 47 tube.
https://philcoradio.com/library/download...l.%201.pdf
It was a playing set when I started re-building bakelite blocks. Part #28 was rebuilt without issue. While awaiting a resistor order I rebuilt part #47, 3615-E block with a single .05 mfd cap. Replaced the cap and when I reinstalled I get virtually no reception now. This block only has two connecting tabs. Part #45, a 51k ohm resistor measures 58k. The block terminal where this resistor connects also has two white wires. One short wire terminates at the first IF Transformer. This wire was brittle and loosely connected. I replaced it but no change in behavior. Replaced the 24 tube at this IF with no change.
When the volume is turned all the way down I hear a weak reception from our strongest local station. When I turn up the volume all audio drops with an occasional crackle as I work it's range. Only fully turned down does any reception come through, weakly at that. The documentation I have doesn't show the volume pot values as I wanted to verify it was still good. I cross referenced to a few 30's era Philco parts booklets I have but none list its value.
I removed the bakelite block connections and measured the newly installed cap, still a solid .05mfd. I connected my signal generator to the set but could not pick up a signal anywhere. I'm missing a basic troubleshooting step here and looking for assistance on next step to identify what's gone wrong.
Many thanks,
Paul