[Elecraft] PC boards for the K2 RIT-SPLIT LED Mod

Wed Oct 29 23:49:04 2003

Having recently installed this mod, using a PCB I manufactured myself, I
second what Tom said regarding the intricacy of this mod.  Here are a few
things I learned while doing this mod:

- A 3/32 (.09375) inch hole in the front panel is a perfect size.
- If you have one, a countersink bit works much better at widening the front
panel hole on the back side of the front panel.
- Mouser Electronics sells a Chicago Miniature LED (Mouser P/N 606-4300F1LC)
that works perfectly.  It's rated at 2mA and provides plenty of brightness.
- I placed a piece of good quality black electrical tape on the back side of
my PCB for added protection.
- The screw that holds the PCB in place will need to be replaced with one
that's 1/8 inch longer to compensate for the added thickness of the mod PCB.
- There's a slight flicker in the LED.  It is very slight, but some may find
it annoying so you might want to check it out before drilling a hole in your
front panel.
- I used a 910 ohm resistor instead of the 870 ohm listed in the mod.  The
best thing to do is to divide your LED's forward voltage by its rated
current.  For me that was 1.8V divided by .002A which came out to 900 ohms.
- I used a dial caliper with a depth pin to determine the length to trim the
LED leads to.  For my K2 it was 19/32 inch.  Yours may be slight different,
but 19/32 or a bit more is probably a good starting point.
- I bought two LEDs in case I messed one up by trimming the leads too short
or something.  They're only 35 cents each.
- Since the maximum voltage into the circuit is 4V, you can safely use a
6.3VDC capacitor which is a pretty small cap physically.  My cap was 4mm
diameter by 6 mm long and it fit with plenty of room to spare.
- I applied some masking tape to the front panel and located my lines by
finding the centers of the adjacent switch holes.  I drilled my hold at the
intersection of the two lines.  Use a drill press if you have one.
- Buy a new 3/32 inch drill to drill the hole.  It's worth the 99 cents or
so to get a nice clean hole.
- Use a black magic marker to "touch up" the exposed aluminum inside the
hole which is visible on the front panel after the hole is drilled.
- TAKE YOUR TIME.  I spent most of an afternoon doing this mod working
slowly but surely to get it right a not mess up my K2's front panel.

73,

Bill...
AIØC

-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Tom Hammond
Sent: Wednesday, October 29, 2003 12:04 PM
To: [email protected]
Subject: [Elecraft] PC boards for the K2 RIT-SPLIT LED Mod

In response to an unexpectedly good turnout for PC boards for the K2 
RIT-SPLIT LED Mod, I have just etched up a batch of 100 boards.

As I have mentioned previously, this is NOT a mod to be undertaken lightly! 
It requires a fairly high level of precision, especially when drilling the 
hole in the front cover of the K2 to accept the LED.