[Elecraft] K1 LCD Illumination

Wed Jan 1 13:45:01 2003

K1ILLUM.TXT
I prefer the LED approach for low power consumption and
long life.   No switch is a good idea.  Here are saved files
from 23 Jan. 2001/and 2002 for K1 LCD illumination, another approach
James Panzitta N2CAU used a mini-lamp  Radio Shack 272-1141
It is 12 volts at 25 mA.
Tie point for 12 volts is pin 16 and ground on the front pc board RF
panel 20 pin IC socket.  There is
no switch.  N2CAU   [email protected]

From: "Sandy, W5TVW" <[email protected]>
Date: Wed, 15 May 2002 15:28:44 -0500
Subject: Re: [Elecraft] K1 illumination

Well!  I took the "plunge" today!  Local "Rat Shack" store had the 
yellow and the white LEDS.  I bought both.  Like the white ones the
best.  They are expensive....but makes the K1 a real 'night-time' 
radio now!  My total receive drain is 58 ma. with 13.5 volt supply.
Illumination looks the same on the 8 "AA" Ni-MH cell supply!
I used stock number 276-320.  
I picked up the ground on the "loop" terminal and the +12 volts on
pin 16 of the RF board 20 pin socket.  Used #20 insulated hookup wire
as it was "stiff" enough to support the LEDs.  A 1500 ohm 1/4 watt
carbon resistor interconnects the LED's over the LCD pins.  Strips of
stragetically placed #33 Scotch electrical tape used as insulators and
also "masks" to minimize light going towards the RIT/XIT LED and
switch cutouts.

This would be a VERY worthwhile "mod" to incorporate in a future
Panel PCB revision!  Also, some "flat" high intensity white or yellow or
green LEDs would be better than the round 5mm sized ones.

Thanks to all for the suggestions!  I originally thought of using the
teeny-tiny grain of wheat 12 v. lamps, but this adds no additional
current
drain worth talking about!  Additionally, they will probably NEVER
need replacement!

73,
Sandy W5TVW
K1 S/N 1178

N4SO
Ken Brown
Mobile, AL/EM50tk
NorCal-20/5 watts/4 ele. beam
[email protected]

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