01-23-2017, 01:16 PM
Okay, so I've completed the electrical (cap and resistor) restoration of this chassis #26 radio I mentioned in my first thread, but I'm having a real Ohm's Law brain freeze with the series heater string. Unlike most models like this, the series dropper consists of 175 ohm and 103 ohm (pilot tap) instead of the more common 175 ohm and 53 ohm. Either way, I figure with 120 volt line and tube drop of 89 volts, the drop across the resistors together is 31 volts. Assuming 150 mA current, the resistors should total 207 ohms, instead of my 278 ohms or the seemingly more common 228 ohms.
This all came about because after I complete the re-cap and power up, I like to check voltages. I found two things: the voltage across the pilot (#47) was about 3.75 volts, and more curious, the heater voltage on the 35A5 was 30 volts. All other heaters were normal. Any suggestions?
One other thing is the coil-capacitor combo, part #4 was missing (probably from a previous butcher job). Is this item necessary, and if so, how would I build one?
This all came about because after I complete the re-cap and power up, I like to check voltages. I found two things: the voltage across the pilot (#47) was about 3.75 volts, and more curious, the heater voltage on the 35A5 was 30 volts. All other heaters were normal. Any suggestions?
One other thing is the coil-capacitor combo, part #4 was missing (probably from a previous butcher job). Is this item necessary, and if so, how would I build one?