Installation - Kenwood TKR-750 Service Manual

1. External Power Supply Connection
(Rear Connectors) : See Page 3
This unit has two external power supply connectors :
Main DC and Backup.
If an external DC power supply is connected to the main
DC connector and a backup battery is connected to the
Backup connector at the same time, the DC power supply
switches to the battery automatically if power failure occurs.
Therefore, the operation of the repeater can be continued.
If the battery is used, but both the battery and power sup-
ply need not be connected (if an external switch is used or if
only a solar battery is used), connect it to the Backup con-
nector, not the Main DC connector. Current consumption
can be reduced by approx. 120mA because the relay is not
used.
If it is installed when the temperature at the repeater site
is below freezing, check whether the switch (relay) works
properly after installation.
2. Voice Scrambler
It operates only during base operation. The voice is not
scrambled when it is repeated.
2-1. Modification
1) Remove R742 and R653 on the TX-RX unit (B/2) : control
section.
2-2. Connection
1) The functions of pins of CN601 on the TX-RX unit (B/2) :
control section are shown in the figure.
2) Join the CN601 connector to the voice scrambler board
via the E37-0808-05 connector cable.
When the operation is checked in PC test mode after the
modification, and the maximum deviation is adjusted, the
voice from the local microphone is not modulated. In this
case, remove the CN601 12-pin (PTO) cable and connect it
to the land of the display unit (X54-333) from the voice
scrambler. The voice from the local microphone can be
modulated in PC test mode.

INSTALLATION

TX-RX unit (B/2) control section
Component side
R653
TXO (MIC signal output)
RXI (RX audio signal input)
AC (Audio control signal output)
BC1 (Scramble code output 1)
BC2 (Scramble code output 2)
BC3 (Scramble code output 3)
BC4 (Scramble code output 4)
CLRC (Clear code for scrambler)
DEO (Detection signal output)
PTO (PTT signal output)
TKR-750
CN604
CN605
Fig. 1
CN601
1
TXI (MIC signal input)
PTI (PTT signal input)
5C (5V output)
GND
14
Fig. 2
Display unit
Foil side
PTO
Fig. 3
CN606
Voice
scrambler
Display
unit
13