I had occasion to take the front off my K1 to check something so I went ahead and added some appropriately sized heat shrink over the ATTN/RIT LED and now absolutely no light spill from the LED’s.
Well, I have a thing for K1’s and have built several over the years. For me, it’s everything a QRP rig should be.
I sold my last one that was totally tricked out with everything you could possibly put on a K1 including the spot filter LED, ATU, Noise blanker and Elecraft backlight kit.
Well that was a stupid move which I regretted. A friend of a friend had one on the shelf that he wanted to get rid of but it was totally stock with NO added features. I set out to bring it up to snuff.
My first task was to make a display backlight because the display is very hard to read without some direct light on it. Since there are no more backlight kits available from Elecraft I went looking for some ideas. I found some posts on the Elecraft reflector about using LEDs on either side of the display. That seemed like a good idea so I ordered some green LEDs. Since LEDs come in different voltages, I got some small LEDs rated at 3V. Using 2 on each side of the display wired in series, it enabled me to tap into the 12V supply on the display board without using any resistors to modify the voltage.
I used some stiff white paper and cut a couple of strips on either side of the display allowing for a couple of cutouts for a capacitor and resistor on the board and laid the paper down with a couple of very small dots of 3M blue tak (if you never heard of it, get some…it’s very handy stuff). I mapped out the positions of the leds making sure I got the sequence of the leads correctly; Cathode(-) to Anode (+) to Cathode to Anode and so on until the last LED lead was + which connected to the ground of the board on the left.
I finished it off with an 8mm strip of velcro material which was still enough to hold its shape and yet allow me to snake it around the components. I used the blue tak to keep it in place. This helps with light spill from the LEDs. It’s not perfect and there still is some minor light spill but for me it’s perfectly acceptable.
Here’s a picture of the final layout. The 12V is coming from pin 16 of the IC at the bottom right of the board to the ground (red wire top left).
Here’s a picture of what it looks like from the front panel with power on. There’s still a slight amount of spillover to the RIT/XIT LED but when RIT of XIT is activated the spillover is completely overridden. I decided to live with that instead of further attempts too completely eliminate spillover. A simple solution would be a length of heatshrink from the base of that LED to the underside of the front panel.