Remove the six screws that hold the cover.  It won't be necessary to
remove the circuit board to install the state machine.  Remove the jumper
from JP6.  If you wish, drill a hole in the front panel just to the left
of the word "THRESHOLD" and above the DCD led.  The hole size should be
correct for the led that you wish to install.  The led anode can be tied
to any +5 volt source, and a 1000 ohm  1/4 watt resistor is connected in
series with the cathode .  The other end of this resistor will be connected
to the orange wire.  This hookup is optional.
Connect the wires as follows:

BROWN - (+5 volts) - Connect to U8, pin 14.

RED - (Ground) - Connect to  U17 pin 7.

ORANGE - (LED)  - Connect to cathode of installed led via a 1000 ohm resistor
(described above).

YELLOW  - (DCD) - Not connected

GREEN - ( -DCD) - Connect to center pin of JP6.

BLUE - (Clock) - Connect to U8, pin 13 (74LS393).

VIOLET - (CD IN) - Connect to the pin on JP6 that is closest to the front panel.

GRAY - (NRZI) - Connect to U15, pin 6.

Important:  If you have the TAPR Modem Disconnect board installed, follow the  
directions given in the kit's instructions.
Insulate the state machine board with some electrical tape, replace cover
and put the screws back in .  This completes the installation of the state
machine board.
Operation:  Adjust the audio level from the VHF receiver such that the tuning
indicator fully spreads on the station with the weakest audio (lowest
deviation) on the channel.
Set the THRESHOLD control so that ANY station's audio will light the factory
DCD LED, as well as noise from unsquelched audio.  The DCD LED should go out
when there is no signal (squelched audio or full quieting from a carrier).
Note:  The DCD modification may affect Morse reception at certain speeds.  
It seems to not affect AMTOR operation or BAUDOT.  It is recommended that
an additional LED be mounted on the PK-232 front panel per the instructions
given.  Proper tuning of signals in all modes will be easier if this is done.  
It is important that the new LED as well as the old DCD LED be illuminated
during MORSE and BAUDOT operation for proper decoding by the PK-232.

There it is.  These are corrections and rewording to the TAPR
instructions that came with the DCD state machine.  The last paragraph
was taken directly from these instructions.

73  Dave, N2DS  @ KC2AZ.NY

GW1NGL NA7KR Kevin Roberts Ham Radio

Page last updated on 09/10/2012 by Kevin Roberts NA7KR a colection of Ham Radio and Electronic Information