[Milsurplus] GRC-9 with LED dial light experiment

[Hubert Miller]

Once I get fired up about something, it's hard for me to drop.
I had around an LED nightlight, one from a discount grocery, not much money.
It has a light level sensor, so it only comes in in dark, and you can control the 'volume' of light by partially
obscuring the sensor. I had planned at some time in the future disassembling it and drawing out the circuit.
Well, I thought about the bright white LED in this thing, and....i grabbed it and cut out its heart.
I rigged it up to 3 VDC and a resistor sub box and then hung the LED behind the dial scale of the GRC-9
receiver. Gentlemen, and Ladies, I am convinced B+ series LED is the way to go. I found even with 6 mA
of DC, it was plenty bright, in fact very bright. In fact, I am questioning my sanity right now, because it's so
bright before even making it to 10 mA. I do not know what the actual max safe current rating of this LED is !
So, the possible new LED circuit would be to interrupt the B+ from the transmitter supply, run it to the LED,
and back to the plate circuits. I recall now that there may be multiple B+ sources on the connector for
different functions, but I don't want to recover my GRC-9 manual right now. But this is the essence of it.
When you wire up the LED, you use a stiff wire anchored somewhere nearby; then you can position the
LED just right. I am sold on this idea. You lose only 3 volts off the B+ top and no extra current drag for
having the dial light on all the time. Practically no extra heat is generated. And it should last ages longer
than any incandescent bulb. The pushbutton could be repurposed for a 100 kHz calibration signal.
I tried to get a photo, but the camera just can't deal with the super high contrast, so the dial numbers
can't be seen in this photo. Yes, I did try a couple styles of yellow LEDs, but they were totally useless.
That spurred the curiosity to see what a bright white would do.
-Hue

[A person in a dark room  Description automatically generated]

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