[Elecraft] K1 LCD BaCKLIGHT

[Louandzip]

 Sounds pretty similar to what I did.  The white rectangle in my photo is a piece of white sticker vinyl stuck to the PCB under the area where the LCD mounts  The two LEDs were sanded down with a Dremel tool and sanding drum to get the light to diffuse and also to make them small enough to shine behind the LCD panel.  The two LEDs and a 680ohm current limiting resistor are all wired in series and draw a total of ~12ma off the 12V supply.  Parts and wires are held in place by dabs of hot glue. 

Here's a closeup of an original and modified LED. 

https://www.dropbox.com/s/vsf64g05jgc4mbl/100_0054.JPG?dl=0




    On Saturday, December 4, 2021, 11:09:25 AM MST, David Gilbert <ab7echo at gmail.com> wrote:  
 
 
I made my own backlight for my K1 before the Elecraft version came out.  
It was actually more of a sidelight, but it works fine.  I took a white 
LED, sanded the plastic case to make it more diffusive, and fed it off 
the 12 volt buss with a current source made from a gate-source connected 
FET.  It wasn't difficult to do.

I don't remember which FET I used, but an LM334 (very inexpensive TO-92 
current source IC) and a 1/4 watt resistor would work even better, and 
today's LEDs are certainly much brighter than the ones I had available 
back when I did this.  Better choice of colors as well.  ;)

73,
Dave   AB7E


On 12/4/2021 8:57 AM, Don Wilhelm wrote:
> Ken,
>
> The K1 LCD backlight is no longer possible.  The original used half of 
> the K2 backlight strip which is no longer available and the new K2 
> strip is too thick to fit under the K1 LCD.
>
> 73,
> Don W3FPR
>
> On 12/3/2021 11:39 PM, Ken Brown wrote:
>>   Need the best modifications for back lighting of the K1.
>> This version never had the K1 LCD Backlight Kit.
>>
>> Ken
>> Elecraft K1 nr. 260
>>
>
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