05-16-2020, 02:26 PM
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Thanks,
FWIW the oscillator is wired exactly as I found it and according to the print. The only difference in that oscillator circuit is I found a choke connected at Pin #4, 7J7, G3. The schematic shows a solid wire. The choke was factory I'm sure. The color bands indicate 2 MH. I replaced it with a 2.2 MH. I have also tried a solid wire in that position like the schematic indicates. There is no mention of that choke in any of the literature I have found so far.
I've just taken a quick glance at that circuit and with the exception of the 330 ohm resistor on the cathode of the 1232/767, (illustration #7,) which is old but checks good, I have replaced all of the passive components in that circuit up through the 7J7. That includes all resistors, all the capacitors, including the three mica caps, illustration numbers 6, 14, 32. These have all now been replaced with high end mica caps I got from Mouser.
I did replace the choke and 10K resistor from the plate of 1232 with a solid piece of wire.
The replacements are all new parts. I intend to check my work again to make sure I didn't install any wrong values and I will check values to make sure I didn't get a bad part. I will once again make sure everything is wired as it is supposed to be.
Coil #28 has been a problem from the get go. It had a broken primary winding which I repaired 4 times before it stayed. I have no idea how far up that coil the break(s) go. It now has continuity and I have good plate voltage through that circuit.
I have tried 3 different components in that position. The original coil which I repaired, a 2.2 MH choke, (In stock I also have a 10 uH, 47 uH and a slug tuned 100 uH I could try I that position if you think it would make a difference,) and a coil from a Philco parts chassis. They all produced excellent plate voltage but no oscillation. I now own this slug tuned oscillator coil, https://www.tubesandmore.com/products/co...oscillator
which I'm experimenting with in that position. Could too much inductance at that position in the circuit block the AC or sufficient AC from returning to the grid?
Tom
Thanks,
FWIW the oscillator is wired exactly as I found it and according to the print. The only difference in that oscillator circuit is I found a choke connected at Pin #4, 7J7, G3. The schematic shows a solid wire. The choke was factory I'm sure. The color bands indicate 2 MH. I replaced it with a 2.2 MH. I have also tried a solid wire in that position like the schematic indicates. There is no mention of that choke in any of the literature I have found so far.
I've just taken a quick glance at that circuit and with the exception of the 330 ohm resistor on the cathode of the 1232/767, (illustration #7,) which is old but checks good, I have replaced all of the passive components in that circuit up through the 7J7. That includes all resistors, all the capacitors, including the three mica caps, illustration numbers 6, 14, 32. These have all now been replaced with high end mica caps I got from Mouser.
I did replace the choke and 10K resistor from the plate of 1232 with a solid piece of wire.
The replacements are all new parts. I intend to check my work again to make sure I didn't install any wrong values and I will check values to make sure I didn't get a bad part. I will once again make sure everything is wired as it is supposed to be.
Coil #28 has been a problem from the get go. It had a broken primary winding which I repaired 4 times before it stayed. I have no idea how far up that coil the break(s) go. It now has continuity and I have good plate voltage through that circuit.
I have tried 3 different components in that position. The original coil which I repaired, a 2.2 MH choke, (In stock I also have a 10 uH, 47 uH and a slug tuned 100 uH I could try I that position if you think it would make a difference,) and a coil from a Philco parts chassis. They all produced excellent plate voltage but no oscillation. I now own this slug tuned oscillator coil, https://www.tubesandmore.com/products/co...oscillator
which I'm experimenting with in that position. Could too much inductance at that position in the circuit block the AC or sufficient AC from returning to the grid?
Tom
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