01-10-2024, 08:37 PM
I know this thread goes back a bunch of years, but I am currently restoring a Model 90 with the one 47 tube also. I wanted to confirm what was originally posted and provide some additional information, including the other differences noted.
I also have a 03137 for the Tone Control. I was planning to replace the existing caps as noted in the "Philco Condensers and More" booklet by Ray Bintliff. They are 0.015, 0.01 and 0.01. It also lists the 4037-A, shown on the schematic, as having the same values.
Should the 0.015 be smaller, as mentioned, 0.006? Then what about the other two?
All the mention of Shorted, Series, Parallel has me confused. The switch just puts each subsequent cap in Parallel, which increases the Capacitance as the switch increments. Right?
My 03137 also had 4 wires coming out of the tar to the 3 contacts. 2 were on the second contact. I tried to measure the existing ones, but I think they were too far gone to make sense. I got 0.008, 0.023 and 50pf!
I was hoping to clarify this, prior to re-assembling, but will probably experiment with the values that I feel give the best response.
I also had the extra capacitor block across the Choke. It was a #4989-J, 0.01mf.
I also had a #3903-P for Item #28, Coupling cap between 1st and 2nd Audio. I think 0.01mf is the correct value, buy Ray's booklet shows it as a 0.1mf.
I also added the resistance value to Ray's Table for the Choke #4951, 460 ohms in my set.
I also have a 03137 for the Tone Control. I was planning to replace the existing caps as noted in the "Philco Condensers and More" booklet by Ray Bintliff. They are 0.015, 0.01 and 0.01. It also lists the 4037-A, shown on the schematic, as having the same values.
Should the 0.015 be smaller, as mentioned, 0.006? Then what about the other two?
All the mention of Shorted, Series, Parallel has me confused. The switch just puts each subsequent cap in Parallel, which increases the Capacitance as the switch increments. Right?
My 03137 also had 4 wires coming out of the tar to the 3 contacts. 2 were on the second contact. I tried to measure the existing ones, but I think they were too far gone to make sense. I got 0.008, 0.023 and 50pf!
I was hoping to clarify this, prior to re-assembling, but will probably experiment with the values that I feel give the best response.
I also had the extra capacitor block across the Choke. It was a #4989-J, 0.01mf.
I also had a #3903-P for Item #28, Coupling cap between 1st and 2nd Audio. I think 0.01mf is the correct value, buy Ray's booklet shows it as a 0.1mf.
I also added the resistance value to Ray's Table for the Choke #4951, 460 ohms in my set.
Thanks
John N3MUN
