Elecraft KAT2 User Manual

Page 12

The K2’s AUX RF connector (RF-P6) is the same type used for the internal battery connector (RF-

P3). To avoid damage to the ATU or to the K2, add some type of unique marking to RF-P6 and to its
mating ATU connector (J7). Use model paint, nail polish, or some other permanent medium.

Before handling the microprocessor in the following step, touch an unpainted, grounded surface or

put on a grounded wrist-strap.

Install U1, the PIC16C77 microprocessor, into its socket on the ATU Control board. The notched or

dimpled end of U1 goes to the left (towards R6). Make sure all pins are fully mated and that none are bent.

Plug the L-C board into the Control board as you did earlier, mating P4 with J4 and P5 with J5. Be

very careful to avoid bending any pins on P4 and P5. Press the two boards together along their full length.

Secure the Control board to the L-C board standoffs using two 4-40 screws and two #4 split lock

washers. These lock washers go between the screw heads and the PC board, not between the PC
board and standoffs as on the L-Cboard.

Turn the K2 ON and use the

D I S P L AY

button to check the receive-mode current drain (for example,

"i0.20", which shows the K2 drawing 200 mA or 0.2 amps). Write this number down. Then turn the K2 off
and disconnect the power supply and/or battery.

Remove the six screws identified below from the K2 top cover. Note: screws #3 and 4 must be

removed from the side panels, leaving two 2-D fasteners attached to the top cover. This is very
important since leaving these 2-D fasteners on the side panels would interfere with routing of the ATU
cables in later steps. If you remove the top cover in the future, always remove only the screws shown.

Remove the top cover by lifting it from the back end. Disconnect the speaker and battery cables.