Kenwood TKR-750 Service Manual

Also see for TKR-750: Brochure & specs Service manual Function reference Service manual Instruction manual

13TKR-7501. External Power Supply Connection(Rear Connectors) : See Page 3This unit has two external power supply connectors :Main DC and Backup.If an external DC power supply is connected to the mainDC connector and a backup battery is connected to theBackup connector at the same time, the DC power supplyswitches 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 ifonly a solar battery is used), connect it to the Backup con-nector, not the Main DC connector. Current consumptioncan be reduced by approx. 120mA because the relay is notused.If it is installed when the temperature at the repeater siteis below freezing, check whether the switch (relay) worksproperly after installation.2. Voice ScramblerIt operates only during base operation. The voice is notscrambled when it is repeated.2-1. Modification1) Remove R742 and R653 on the TX-RX unit (B/2) : controlsection.2-2. Connection1) 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 boardvia the E37-0808-05 connector cable.When the operation is checked in PC test mode after themodification, and the maximum deviation is adjusted, thevoice from the local microphone is not modulated. In thiscase, remove the CN601 12-pin (PTO) cable and connect itto the land of the display unit (X54-333) from the voicescrambler. The voice from the local microphone can bemodulated in PC test mode.INSTALLATIONCN606CN604CN605CN601114R653R742TX-RX unit (B/2) control sectionComponent sidePTODisplay unitFoil sideTXI (MIC signal input)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)PTI (PTT signal input)CLRC (Clear code for scrambler)DEO (Detection signal output)PTO (PTT signal output)5C (5V output)GNDCN601114VoicescramblerDisplayunitFig. 1Fig. 2Fig. 3