12-21-2025, 11:55 PM
Welcome 37 Cord!
The The basic schematics for car vs home 6tube superhets are rather similar. The problem is that most home radios (popular) have IFs around 455 KHz (common) and most 1937 model Philco car radios (rare) have lower IF frequencies, so scavenging one from a home radio will be difficult. If this winding has many turns and you can reach the green rot area and can find the break, removing a few turns will change the resonant frequency of the coil but not beyond the range of the "padding" condenser adjustment. If the winding that you repaired (Some would refer to this as the tickler, as it connects via capacitor to the "grid plate" of the oscillator section of the tube) is only a single winding, it can be removed, counting the number of turns as you remove it, getting to the lower layer, repairing the layer, then rewinding the tickler. (What you referred toas the "screen grid" is actually the plate of the oscillator. This is often referred to as a "plate grid".).
By 1935 or so, the basic circuit of an AM Broadcast band radio was fairly standardized with the only difference being the presence or absence of an RF amplifier and the style of tubes used (large pin vs octal, vs Loctal vs miniature) and heater voltages.
The 6A7 (or 2A7 or 6SA7) is a common "pentagrid" converter and the circuit is rather common across manufacturers. 455-470 is a common IF frequency. However, newer radios have oscillator sections of the tuning condenser that have much less total area than the tuning capacitors used in older car and home radios that tended to be the same area as the RF section. Therefore, with the correct capacitor in series with the coil, it may be possible to get an oscillator coil from a modern (1950s) AA5 radio to work in this set. Most tuning caps have a capacity from 10pF (full open) to 365 pF (full mesh). For your set, the oscillator is tuned to a frequency 260 KHz higher than the frequency of the station tuned. The heterodyning of these 2 signals gives you a signal of 260 KHz, amplified by the IF stage. Don't ask me the value of capacitor needed to make this coil oscillate at 260KHz. There are HAMs and EEs on this site or you may be able to figure the calculation based on the value of the tuning cap, the inductance of the oscillator coil, the value of the cap in series with the oscillator coil, etc.
Good luck with the radio, please post a pic of it and of the Cord; it in itself is a technological marvel.
The The basic schematics for car vs home 6tube superhets are rather similar. The problem is that most home radios (popular) have IFs around 455 KHz (common) and most 1937 model Philco car radios (rare) have lower IF frequencies, so scavenging one from a home radio will be difficult. If this winding has many turns and you can reach the green rot area and can find the break, removing a few turns will change the resonant frequency of the coil but not beyond the range of the "padding" condenser adjustment. If the winding that you repaired (Some would refer to this as the tickler, as it connects via capacitor to the "grid plate" of the oscillator section of the tube) is only a single winding, it can be removed, counting the number of turns as you remove it, getting to the lower layer, repairing the layer, then rewinding the tickler. (What you referred toas the "screen grid" is actually the plate of the oscillator. This is often referred to as a "plate grid".).
By 1935 or so, the basic circuit of an AM Broadcast band radio was fairly standardized with the only difference being the presence or absence of an RF amplifier and the style of tubes used (large pin vs octal, vs Loctal vs miniature) and heater voltages.
The 6A7 (or 2A7 or 6SA7) is a common "pentagrid" converter and the circuit is rather common across manufacturers. 455-470 is a common IF frequency. However, newer radios have oscillator sections of the tuning condenser that have much less total area than the tuning capacitors used in older car and home radios that tended to be the same area as the RF section. Therefore, with the correct capacitor in series with the coil, it may be possible to get an oscillator coil from a modern (1950s) AA5 radio to work in this set. Most tuning caps have a capacity from 10pF (full open) to 365 pF (full mesh). For your set, the oscillator is tuned to a frequency 260 KHz higher than the frequency of the station tuned. The heterodyning of these 2 signals gives you a signal of 260 KHz, amplified by the IF stage. Don't ask me the value of capacitor needed to make this coil oscillate at 260KHz. There are HAMs and EEs on this site or you may be able to figure the calculation based on the value of the tuning cap, the inductance of the oscillator coil, the value of the cap in series with the oscillator coil, etc.
Good luck with the radio, please post a pic of it and of the Cord; it in itself is a technological marvel.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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