|USING (modern bright) Light Emitting Diodes as Pilot Lights (LAMP
REPLACEMENT) by Earl Andrews VE3AB (www.hamelectronicsmagazine.com)
new article November 28th 2014 (this article is under construction)
You can use a 470 ohm resistor as a current limiting resistor. If you dont use a resistor to limit current from you 12v or 13.5
line or source voltage..the LED will burn up and actually smoke ! I found this out ! Fortunately..the LEDs from China are not
all that expensive.
I used a 510 ohm resistor and various pieces of various sized heatshrink tubing to ruggedize and protect the LED and the
leads and the resistor and the solder connections. I also used some hookup wire.
The first LED was OK but I added a second LED (yellow) just for the heck of it and it brightened up the display a wee bit
I filed down the front of the LED and filed a bit to roughen the
side surfaces as well. Supposedly..this diffuses the light better.
The White Light Led was used in the rubber holder but I added
a second yellow LED on top of the meter to add a bit more light.
Both LEDs are visible and are close to each other near the top of the meter in the
FT301. I later moved the yellow LED over to the right towards the center of the meter. I
just sort of wedged it in where it would stay put even without tie downs. These LEDs
were not hot to the touch and are well insulated to prevent shorting out the circuitry.
The life span should be much longer than incandenscent lamps.
IF YOU WANT to try this yourself..I can make up a mini kit of appropriate sized heatshring tubing,
some bright LED diodes..some 510 ohm and/or 470 ohm reistors and anything else you might need
to make a project or two. MY PRICES ARE only about 25 percent over the cost of the items (I buy
stuff in bulk) and postage within Canada is $2 or to USA is $4 ..which is much lower than the ebay
|THIS IS AN FT301 I am currently working on. I had to change the meter (as it was busted) and change the front tuning knob
as it was also cracked - (might have been damaged during shipping to a previous owner).. and I decided to try LEDs to
replace the incandesent lamps which were not working. -- I have quite a few extra (spare) parts for FT301s, ATlas 210x, Ten
Tec Argonauts (509 through 515s) To see a listing of JUNKER RADIOS for parts that I have around here: go visit this page.