[Elecraft] KAT2 mod

[Ingo, DK3RED]

Hello K2 user,

Some user looking for a methode to load the internal battery in the
switched off status of the K2 without the reverse-polarity protection
diode D10 in the line and without any other jacks or so. Here is my
solution.

Modification part 1

- Switch off the internal battery on the rear panel.
- Disconnect any power supply or battery conncted to the DC power jack.
- Remove the bottom cover with the tilt and place the K2 with the front
  panel on the left side and the bottom side up.
- Cut two isulated hookup wires. First one 10.4 cm = 4.1 inch. Second one
  11.8 cm = 4.7 inch. Strip all 4 ends of the wires using 5mm (0.2 inch)
  and form small loops on each end.
- Solder the short wire from the left solder point of D10 to one of the
  free (most left) solder points of S1 (on-off switch). Solder the long
  wire from the right solder point of D10 to the other free solder point
  of S1. Note: With "free" I mean the points without any connection to
  other parts of the board. You can interchange these both points on the
  switch without problems.
- Replace the bottom cover and place the K2 again in the normal position.

Modification part 2

- Remove the top cover and the connections to the RF board.
- Replace the red wire from the (+) battery terminal to the battery
  switcher with a new one (without diode and resistor).
- Replace all connections to the RF board and the top cover.

Important note

The functions of reverse-polarity diode D10 and the internal
self-resetting fuse F1 are the same after the modifications. But the
internal battery is now direct connected to the 12V DC jack in the
switched off K2, so the battery is now NOT protected (no reverse-polarity
protection or shorting protection) in these (off-)status.

Using an external lader

- Switch off the K2.
- Plug in the lader (i.e. solar panel with controller) in the DC jack.
- Switch on the internal battery on the rear panel.

The modification works UFB here in the K2 #01118 with an accumulator
charger for the trouser-pocket. For more informations see the GIF picture
on http://www.t-online.de/~dk3red/b/k2_lader.jpg. I will put in the next
days a PDF file on my homepage and post the URL here.

-- 
72/73 de Ingo, DK3RED   Don't forget: the fun is the power!

   dk3red@t-online.de   http://www.t-online.de/~dk3red
       DL-QRP-AG #824   http://www.dl-qrp-ag.de