Kenwood TK-780 Service Manual page 23

Scrambler board
Code 4 (C4)
Code 3 (C3)
Code 2 (C2)
Code 1 (C1)
( ) : PCB silk name
TXAI (TXAI)
RXAI (RXAI)
OPT (OP)
MPTT (MPTT)
SB (SB)
GND (GND)
RXAO (RXAO)
TXAO (TXAO)
Fig 5
C3 C4
OP
C1 C2
TX-RX unit (A/2)
Component side view
SB
GND
MPTT
INSTALLATION
TK-780
(TX-RX A/2 PCB)
(TX-RX A/2 PCB)
(TX-RX A/2 PCB)
(TX-RX A/2 PCB)
R571
Disable
(TX-RX B/2 PCB)
(TX-RX B/2 PCB)
(TX-RX A/2 PCB)
(TX-RX B/2 PCB)
(TX-RX B/2 PCB)
(TX-RX B/2 PCB)
R529
Disable
(TX-RX B/2 PCB)
(TX-RX B/2 PCB)
TXAI
TXAO
TX-RX unit (B/2)
: Control section
Foil side view
RXAI
RXAO
6. PA/HA Unit (KAP-1 : Option)
6-1. Installing the KAP-1 in the Transceiver
The Horn Alert (max. 2A drive) and Public Address func-
tions are enabled by inserting the KAP-1 W1 (3P; white/
black/red) into CN3 on the TX-RX unit (A/2), inserting W2
(3P; green) into CN5 on the TX-RX unit (A/2), and connecting
the KCT-19 (option) to CN2 and CN3 of the KAP-1.
• Installation procedure
1. Open the upper case of the transceiver.
2. Insert the two cables (
KAP-1 switch unit into the connectors on the transceiver.
3. Secure the switch unit board to the chassis with a screw
( ). The notch ( ) in the board must be placed at the
3 2
front left side.
4. Attach the cushion on the top of the KAP-1 switch unit.
Cushion
(G13-1710-04)
3
4
3
2
W1
W2
CN1
CN2
1
CN3
1
CN3
CN5
Fig. 6
6-2. Modifying the Transceiver
• Horn alert
The signal from pin 4 of IC7 on the TX-RX unit (A/2) turns
Q4 and Q6 on and off and drives KAP-1 HA relay to drive the
horn with a maximum of 2A.
The default output is HR1. The relay open output can be
obtained between HR1 and HR2 by removing R1 in the KAP-1.
HR1 (Default) Enable
HR2 Disable
TK-780
) with connectors from the
1
KCT-19
R1 Output form
HR1
HR1
HR2
23