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[split] Philco 1938 Farm Radio
#2

Hi Mt MattKing,

Here is a link to the schematic. It was buried early in the thread, but I am happy to attach it here.

https://philcoradio.com/library/download...l.%201.pdf

Yes, you need 135VDC, 67.5VDC B+ (Neg to chassis), +2VDC (Yes, 2 Volts, Neg to chassis), and "C-", 3V and 7.5V, (Pos to chassis)

For 2V, it would be best to obtain a 3V, 1A "Wall Wart" power supply. Here is a reprint of my previous post about running the filaments on 3V:

The A supply will be the most difficult because you need the most current (500 mA 0r 0.5A) at 2.0V. Since "D" size dry cells provide 1.5V and 2 in series provide 3V, you need to calculate the dropping resistor needed. The good news, is that I am going to do that for you right now:
Below is a chart with each tube in your radio and the current it draws:

1A6 0.060A
32 0.060A
32 0.060A
30 0.060A
19 0.260A

Since these tubes are all connected in parallel, the total draw is 0.5A. Since a resistor has to be added in series to the A Battery connection to the radio to drop the voltage to 2.0V, and current is constant in a series circuit, we need to calculate the resistance needed to drop 1V at 0.5A. So if E=IR then R= E/I. So, if the voltage drop is 1V and the current is 0.5A, then R = 1/0.5 or 2 Ohm. Since the current is constant, in theory a 2 Ohm 1/2 watt resistor is sufficient, use a 2 Ohm resistor at 2 Watt or higher rating.

Since a D Cell delivers only about 1.5Amp Hours, 2 D Cells in series will last 3 hours or less running this radio. 3V 1000 MA "Wall Wart" power supplies can be found for $15.00 or less on the internet. This and the 2 Ohm 2 Watt resistor will power your filaments.

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
[split] Philco 1938 Farm Radio - by Mtmattking - 02-17-2026, 11:19 PM
RE: [split] Philco 1938 Farm Radio - by MrFixr55 - 03-10-2026, 09:50 AM
RE: [split] Philco 1938 Farm Radio - by morzh - 03-10-2026, 07:18 PM
RE: [split] Philco 1938 Farm Radio - by Arran - 03-11-2026, 05:28 AM
RE: Philco 1938 Farm Radio - by MrFixr55 - 02-18-2026, 08:46 AM
RE: Philco 1938 Farm Radio - by Mtmattking - 02-18-2026, 08:42 PM
RE: Philco 1938 Farm Radio - by Mtmattking - 02-19-2026, 07:54 PM
RE: Philco 1938 Farm Radio - by MrFixr55 - 02-20-2026, 09:28 AM
RE: Philco 1938 Farm Radio - by MrFixr55 - 02-20-2026, 10:06 AM
RE: Philco 1938 Farm Radio - by Arran - 03-01-2026, 07:29 PM
RE: Philco 1938 Farm Radio - by Mtmattking - 03-03-2026, 04:19 PM
RE: Philco 1938 Farm Radio - by Arran - 03-03-2026, 09:43 PM
RE: Philco 1938 Farm Radio - by Mtmattking - 03-03-2026, 09:58 PM
RE: Philco 1938 Farm Radio - by Arran - 03-04-2026, 12:25 AM
RE: Philco 1938 Farm Radio - by morzh - 03-04-2026, 10:49 AM



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