01-22-2013, 04:52 PM
I'm currently restoring the chassis of my 42-761EZ. This is the chassis which came out of the cabinet I had so much trouble refinishing this past summer.
It's an AC/DC set, designed to operate from either 115 or 230 volts, and has a metal ballast with jumper wires for 115 volt operation, and two sets of resistance wire for 230 volt operation.
I suspect one or both sections of resistance wire are bad, but that does not matter since it will be powered by 125 volt AC.
This set is another nightmare of rotten rubber-covered wiring, and it's all bad. Yep, all of it is dried out and crumbling.
Anyway, here is my first question on the subject.
This set uses a pilot lamp which connects across the line, but with a Candohm resistor in series with the lamp to drop the line voltage down to the proper voltage.
The original lamp was 34-2397E.
I found a 34-2397 in my 1950 Philco parts catalog. According to it, the lamp is a #53, 12 to 16 volts, 0.10 amps at 15 volts. It is listed as having a cylindrical bulb like a 44 or 47, miniature bayonet base.
The series resistance is 1020 ohms.
So, following Ohm's law, E=IR so 0.10 * 1020 = 102 volts being dropped, so assuming a 117 volt line, this would be correct for this lamp.
However, modern specs for a 53 lamp indicate 14.4 volts at 0.12 amps, with a round bulb like a 51.
All of that really does not matter to me, and here is why.
I am thinking of eliminating the dropping resistor and installing a miniature bayonet lamp which will run on 120 volts. I found types 120MB, 120MB6 and 967, but it looks like I would be sacrificing candle power for the convenience of having no dropping resistor if I used one of those.
The lamp is used to light the top edge of the dial scale, and is movable so only one of the several scales is lit depending on which band is selected.
To me, a 1020 ohm resistor is a very inefficient way to run a dial lamp.
Neon is out of the question as the lamp needs to be very bright to properly light up the edge of the glass dial scale. An LED lamp is an option, as long as it does not generate enough RF to interfere with the proper operation of the radio.
So, I look to you, the Phine Philco Phellows, for your thoughts, suggestions, etc.
It's an AC/DC set, designed to operate from either 115 or 230 volts, and has a metal ballast with jumper wires for 115 volt operation, and two sets of resistance wire for 230 volt operation.
I suspect one or both sections of resistance wire are bad, but that does not matter since it will be powered by 125 volt AC.
This set is another nightmare of rotten rubber-covered wiring, and it's all bad. Yep, all of it is dried out and crumbling.
Anyway, here is my first question on the subject.
This set uses a pilot lamp which connects across the line, but with a Candohm resistor in series with the lamp to drop the line voltage down to the proper voltage.
The original lamp was 34-2397E.
I found a 34-2397 in my 1950 Philco parts catalog. According to it, the lamp is a #53, 12 to 16 volts, 0.10 amps at 15 volts. It is listed as having a cylindrical bulb like a 44 or 47, miniature bayonet base.
The series resistance is 1020 ohms.
So, following Ohm's law, E=IR so 0.10 * 1020 = 102 volts being dropped, so assuming a 117 volt line, this would be correct for this lamp.
However, modern specs for a 53 lamp indicate 14.4 volts at 0.12 amps, with a round bulb like a 51.
All of that really does not matter to me, and here is why.
I am thinking of eliminating the dropping resistor and installing a miniature bayonet lamp which will run on 120 volts. I found types 120MB, 120MB6 and 967, but it looks like I would be sacrificing candle power for the convenience of having no dropping resistor if I used one of those.
The lamp is used to light the top edge of the dial scale, and is movable so only one of the several scales is lit depending on which band is selected.
To me, a 1020 ohm resistor is a very inefficient way to run a dial lamp.
Neon is out of the question as the lamp needs to be very bright to properly light up the edge of the glass dial scale. An LED lamp is an option, as long as it does not generate enough RF to interfere with the proper operation of the radio.
So, I look to you, the Phine Philco Phellows, for your thoughts, suggestions, etc.
--
Ron Ramirez
Ferdinand IN
