KENWOOD TK2160
Service Manual

TK-2160
CIRCUIT DESCRIPTION
20 of the CPU. The signal passes through a low pass CR filter, mixes with the audio signal, and goes to the VCO modulation input. TX deviation is adjusted by the CPU. (2) DTMF/2 TONE High-speed data is output from pin 2 of the CPU. The signal passes through a low-pass CR filter, and provides a TX and SP out tone, and is then applied to the audio processor (IC601). The signal is mixed with the audio signal and goes to the VCO. TX deviation is adjusted by the CPU. (3) MSK (Fleet Sync) The MSK input signal from the IF IC is amplified by IC602 (1/2) and goes to pin 31 of IC 601. The signal is demodulated by MSK demodulator in IC 601. The demodulated data goes to the CPU for processing.
C834 X801 XOUT IC805 Q810 Hi: OFF LOW: ON BSHIFT

Fig. 10 Frequency shift circuit 2) Memory Circuit
Memory circuit consists of the CPU (IC805) and an EEPROM (IC804). An EEPROM has a capacity of 64k bits that contains the transceiver control program for the CPU and data such as transceiver channels and operating features.
IC805 CPU IC804 EEPROM

5. Power Supply
There are 3.5V power supply for PLL circuit and five 5V power supplies for the microprocessor: 5M,5MS,5C,5R, and 5T. 5M is always output while the power is on. 5M is always output, but turns off when the power is turned off to prevent malfunction of the microprocessor. 5C is a common 5V and is output when SAVE is not set to OFF. 5R is 5V for reception and output during reception. 5T is 5V for transmission and output during transmission.

Fig. 11 Memory circuit 3) Low Battery Warning
The battery voltage is checked using by the microprocessor. The transceiver generates a warning tone when it falls below the warning voltage shown in the table. (1) The red LED blinks when the battery voltage falls below the voltage (1) shown in the table during transmission. (2) The red LED blinks when the battery voltage falls below the voltage (2) shown in the table during transmission. Note: The transceiver checks the battery voltage during reception even when, in the FPU, the Battery Warning status function
R834

6. Control Circuit
The control circuit consists of a microprocessor (IC805) and its peripheral circuits. It controls the TX-RX unit. IC805 mainly performs the following: (1) Switching between transmission and reception by the PTT signal input. (2) Reading system, group, frequency, and program data from the memory circuit. (3) Sending frequency program data to the PLL. (4) Controlling squelch on/off by the DC voltage from the squelch circuit. (5) Controlling the audio mute circuit by the decode data input. (6) Transmitting tone and encode data.

is set to �On TX� (default setting). However, the LED does not blink during reception. During transmission, the LED blinks to generate the warning tone of a low battery voltage. (3) The transceiver immediately stops transmission when the battery voltage falls below the voltage (3) shown in the table. A message tone beeps while the PTT switch is released. Battery Case (1) (2) (3) 6.2[V] 7.6[V] 5.9[V]
SB

Li-ion Battery Ni-Cd Battery Ni-MH Battery 6.5[V] 7.1[V] 6.2[V]
R833 88 CPU

1) Frequency Shift Circuit
The microprocessor (IC805) operates at a clock of 7.3728MHz. This oscillator has a circuit that shifts the frequency by BEAT SHIFT SW (Q810). A beat sound may be able to be evaded from generation if �Beat Shift� is set to ON when it is generated in the internal spurious transmission modulated sound of a transceiver.

6.2[V] 6.8[V] 5.9[V]
IC805

6.2[V] 7.0[V] 5.9[V]

Fig. 12 Low battery warning
10