Kenwood M) Service Manual

Also see for TK-2160: Specifications Instruction manual Instruction manual Specifications Service manual

Contents

TK-2160102) Memory CircuitMemory circuit consists of the CPU (IC805) and an EEPROM(IC804). An EEPROM has a capacity of 64k bits that containsthe transceiver control program for the CPU and data suchas transceiver channels and operating features.3) Low Battery WarningThe battery voltage is checked using by the microprocessor.The transceiver generates a warning tone when it falls belowthe warning voltage shown in the table.(1) The red LED blinks when the battery voltage falls belowthe voltage (1) shown in the table during transmission.(2) The red LED blinks when the battery voltage falls belowthe voltage (2) shown in the table during transmission.Note:The transceiver checks the battery voltage during receptioneven when, in the FPU, the Battery Warning status functionis set to “On TX” (default setting).However, the LED does not blink during reception. Duringtransmission, the LED blinks to generate the warning toneof a low battery voltage.(3) The transceiver immediately stops transmission whenthe battery voltage falls below the voltage (3) shown inthe table. A message tone beeps while the PTT switchis released.CIRCUIT DESCRIPTION6. Control CircuitThe control circuit consists of a microprocessor (IC805) andits peripheral circuits. It controls the TX-RX unit. IC805 mainlyperforms the following:(1) Switching between transmission and reception by thePTT signal input.(2) Reading system, group, frequency, and program datafrom the memory circuit.(3) Sending frequency program data to the PLL.(4) Controlling squelch on/off by the DC voltage from thesquelch circuit.(5) Controlling the audio mute circuit by the decode data input.(6) Transmitting tone and encode data.1) Frequency Shift CircuitThe microprocessor (IC805) operates at a clock of7.3728MHz. This oscillator has a circuit that shifts thefrequency 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 internalspurious transmission modulated sound of a transceiver.20 of the CPU. The signal passes through a low pass CRfilter, mixes with the audio signal, and goes to the VCOmodulation input. TX deviation is adjusted by the CPU.(2) DTMF/2 TONEHigh-speed data is output from pin 2 of the CPU. The signalpasses through a low-pass CR filter, and provides a TX andSP out tone, and is then applied to the audio processor(IC601). The signal is mixed with the audio signal and goesto 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 demodulatedby MSK demodulator in IC 601. The demodulated data goesto the CPU for processing.5. Power SupplyThere are 3.5V power supply for PLL circuit and five 5Vpower supplies for the microprocessor: 5M,5MS,5C,5R, and5T. 5M is always output while the power is on. 5M is alwaysoutput, but turns off when the power is turned off to preventmalfunction of the microprocessor.5C is a common 5V and is output when SAVE is not set toOFF.5R is 5V for reception and output during reception.5T is 5V for transmission and output during transmission.X801C834XOUTIC805Q810Hi: OFFLOW: ONBSHIFTFig. 10 Frequency shift circuitFig. 11 Memory circuitIC805CPUIC804EEPROMBattery Case Li-ion Battery Ni-Cd Battery Ni-MH Battery(1) 6.2[V] 6.5[V] 6.2[V] 6.2[V](2) 7.6[V] 7.1[V] 6.8[V] 7.0[V](3) 5.9[V] 6.2[V] 5.9[V] 5.9[V]SB R833R83488IC805CPUFig. 12 Low battery warning