Elecraft KRC2ACC User Manual

ELE C R A F T KR C 2

BA N D D E C O D E R a n d C O N T R O L L E R

Accessibility Upgrade and Operating Instructions

Revision A, March 4, 2004. Copyright © 2004, Elecraft; All Rights Reserved

Introduction

The KRC2 Accessibility Upgrade adds the capability of Morse code announcement of K2
functions. Along with this function, the KRC2 is configured to control K2 functions using KRC2
button combinations.

The upgrade kit adds two parts to the KRC2 circuit board, and replaces the KRC2’s
microcontroller.

If your KRC2 is not yet assembled, make the following changes to the Owner’s manual:

On page 13 of the KRC2 Assembly and operations Manual, between the first and second steps,
insert the two instructions from page 2 of these instructions for installing R5 and SP1. Use the test
procedures from these instructions for testing and initial power-up of the KRC2.

Firmware Requirements

The KRC2 Accessibility Configuration will work with any K2 or K2/100 transceiver with K2
main microcontroller firmware revision 2.01 or later and either the KIO2 or KPA100 options. In
order to use the KDSP2 support functions, the K2 is required to use firmware revision 2.04 or
later.

Upgrade Kit Parts List

The table below lists all parts in the kit. Typical markings on capacitors, as well as resistor

and RF choke color codes, are shown in parentheses.

Ref.

Description

Part No.

Qty

R5

Trimmer Potentiometer, 5K (“502”)

E520009

1

SP1

Miniature Piezo Speaker

E980064

1U1IC, programmed microcontroller, PIC16F877A-I/P

E610019

1

MISC

KRC2 Accessibility Upgrade Instructions

E740071

1

2

Assembly

Disconnect all cables, including power sources, from the KRC2. Remove the two Philips

screws from the bottom cover and remove the bottom cover. CAUTION: Touch an unpainted,

grounded metal surface frequently while handling PC boards and ICs.

Remove the two flat-head Philips screws holding the “2D” fastener at the end of the case

opposite the DB9 connectors, and remove the “2D” fastener.

Remove the Philips screw and washer that holds the PCB to the case. This screw is located

near the end of the PC board opposite the DB9 connectors.

Remove the four male-female hex standoffs that hold the DB9 connectors to the case.

Remove the PCB assembly from the case.

i

The side of the board with IC U1 is the bottom; the opposite side is the top.

Install the 5K trimmer potentiometer, R5, on the bottom side of the PCB. After soldering the
three leads, adjust the pot to its full clockwise position. R5 is used for setting the volume of the
CW tones from the speaker.

Install the piezo speaker, SP1, on the top side of the PCB. The speaker mounting posts must
be mounted flush against the PCB to give proper clearance for the case bottom.

Carefully remove the old microprocessor, U1 using a small screwdriver to pry it gently out of
its socket at both ends. Store U1 in a safe place as a backup.

i

Before handling U1, touch an unpainted, grounded metal surface.

Carefully straighten the pins on the microcontroller, U1 (PIC16F877A). The two rows of pins
must be parallel to each other, with no pins bent. See Figure 4 of the KRC2 Assembly and
Operations Manual.

Orient the notched or dimpled end of the IC with the notched end of its component outline
on the PCB, then press the microcontroller into its socket

3

Case Assembly

Re-install the PCB into the case top following the procedure on page 14 of the KRC2
Assembly and Operations Manual. Use the hardware you previously removed when
disassembling the KRC2.

KRC2 Test Procedure

The KRC2 should be powered from its DC barrel jack using a +12 volt supply for its initial
power-up. No other connections should be made to the unit.

Connect the power source to the unit. After a short delay while the KRC2 performs
diagnostics, the front-panel LED should turn on to its dim level. If this does not happen, turn
power off to the unit and refer to the troubleshooting section.

Driver Relay Test: You will need a DC voltmeter for this procedure. Connect the BLACK lead
(common) to the ground jumper located near J1 on the KRC2. The RED lead should be used to
measure the voltage on each terminal of J6, J7, J8 and J9. Be sure to check the voltage at the side
connector of each terminal. The initial readings should be 0 volts on each terminal.

The Tap/Hold Rule: Each of the pushbutton switches on the top of the KRC2 has two functions,
one activated by a TAP (short press) and the other activated by a HOLD (long press, about 1/2
second). To highlight this in the text, we use two different typographical styles to identify
switches: T AP and H OLD . Shift functions require a key to be held, then a second key to be
pressed. These are indicated by HOL D TA P .

Holding

F3

should cause the KRC2 to announce a Morse ‘I’ from the speaker, and brighten

the LED. Now tap

F1

to change the driven band terminal. The KRC2 should emit a CW ‘D’. Only
the 60m source terminal should indicate 12 volts. The LED should be alternating between dim and
bright.

Holding F3 and tapping

F1

again should cause the 10m source terminal to indicate 12 volts,

and all others to remain off.

Continue this procedure, Holding F3 and tapping

F1

until all HF source terminals have been

checked.

This completes checkout of the KRC2. Continue to the Final Assembly section on page 16 of the
KRC2 Assembly and Operations Manual.