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Zenith 7H822 Dial light? - Printable Version

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Zenith 7H822 Dial light? - Eric Adams - 03-31-2014

I have two of these and there is no dial light in either and I can't find one in the schematic. Has anyone ever added one? Is it a good idea to do so?

Here's the schematic

RE: Zenith 7H822 Dial light? - BrendaAnnD - 03-31-2014

These weren't designed to have a dial light. If you were to add one, it would have to be a 120V type, as there is no rectifier tube from which to tap the voltage for a smaller bulb.

RE: Zenith 7H822 Dial light? - Eric Adams - 03-31-2014

Thanks Brenda, that's kind of what I thought. I'll leave it the way it is.

RE: Zenith 7H822 Dial light? - morzh - 03-31-2014

Take a bright LED about 10mA or so. Take a resistor. Take a diode, some 50V Vr will do. Put them in series acrodd any of the 12V filament of one of the tubes.
The diode and the LED should be plugged with the same poalrity and the resistor should be about 1K to 2K.
Try it see how it works.

PS. Do not extract the tube whose filament you used for the LED while the radio is hot.

RE: Zenith 7H822 Dial light? - BrendaAnnD - 04-01-2014

Wouldn't even need the diode, Mike. LED's run fine on AC.

RE: Zenith 7H822 Dial light? - codefox1 - 04-04-2014

Neon pilots complete with mounting stuff and resistor can be had for pennies. Bought a pack years ago and still have some. Use on 120 VAC, no heat, drill one hole and you're set.

RE: Zenith 7H822 Dial light? - Eric Adams - 04-04-2014

Considering the fact that Zenith didn't want to put one in, I'm going to leave it the way it is.

Thanks,

RE: Zenith 7H822 Dial light? - morzh - 04-04-2014

Brenda

It may run fine but it is out of specs. If you have 6 to 12V AC across the LED and it is reversed then you are exceeding the max reverse voltage which for most LED lamps is 4-5V. Hence the diode.