Kenwood TK-5210 Service Manual

Also see for TK-5210: Specifications Instruction manual Specifications Instruction manual Instruction manual

Contents

TK-521017CIRCUIT DESCRIPTIONcontains the transceiver control program for the CPU. It alsostores the data for transceiver channels and operating param-eter that are written by the FPU. This program can be easilywritten from an external devices.The EEPROM (IC2) stores the last channel data, the scanon status, and other parameters.■ Flash memoryNote : The flash memory stores the data that is written bythe FPU (KPG-95D), and firmware program (User mode, Testmode, Tuning mode, etc.). This data must be rewritten whenreplacing the flash memory.■ EEPROMNote : The EEPROM stores tuning data (Deviation, Squelch,etc.).Realign the transceiver after replacing the EEPROM.■ Real-time clockThe clock function is based on real-time clock IC (IC1).When the power supply is off, it is backed up by an internalsecondary lithium battery6-2. LCD (K2 and K3 models only)The LCD is controlled using the bus lines on the connector(CN604) of the control unit (X57 B/5).It corrects the LCD contrast voltage using IC704. Thevoltage corresponding to the temperature is sent to pin 3 ofIC704 from the CPU (IC5) according to the temperaturemeasurement results using a temperature IC (IC4).6-3. Temperature Detection CircuitThe temperature detection circuit detects thetemperature using a temperature IC (IC4) and corrects thethermal characteristic change of the squelch or LCD.6-4. Key Detection CircuitKeys are detected using three shift registers (IC701,IC702, IC703).The KIN signal that is normally pulled down goes highwhen any key is pressed.6-5. Low Battery WarningThe battery voltage is divided using R15 and R16 and isdetected by the CPU (IC5). When the battery voltage fallsbelow the voltage set by the Low battery warningadjustment, the red LED blinks to notify the operator that it istime to replace the battery. If the battery voltage falls evenmore (approx. 5.8V), a beep sounds and transmission stops.Low battery warning Battery conditionThe red LED blinks during The battery voltage is low buttransmission. the transceiver is still usable.The red LED blinks and The battery voltage is low andthe warning tone beeps while the transceiver is not usable tothe PTT switch is pressed. make calls.6-6. VOXThe VOX function can be used only with an externalmicrophone.The VOX (Voice Operated Transmission) function detectsvoice input to the microphone and automatically switchesbetween transmission and reception. However, if ascrambler board is installed (Extended Function VoiceScrambler is selected with FPU), VOX does not operate.If the microphone input exceeds a certain level,transmission automatically begins. If the input falls below acertain level, the transceiver automatically returns to receivemode.The TK-5210 realizes this function using DSP (IC8).6-7. DSPThe DSP circuit consists of a DSP (IC8), a CODEC (IC406)and processes the base band signal. The DSP operates on anexternal clock of 9.216MHz (the same as the CPU), the I/Osection operates at 3.3V and the core section operates at1.5V. The DSP carries out the following processes:• C4FM encoding• Analog FM pre-emphasis/de-emphasis• Vocoder (IMBE) processing between audio codec andmodulation/demodulation• CAI processing, such as error correction encoding• QT/DQT encoding/decoding• DTMF encoding/decoding• MSK encoding/decoding• 2-tone decoding• Compressor/expander processing• Transmit/receive audio filtering processing• VOX processing• Microphone amplifier AGC processing• Audio mute processing• Modulation level processingFig. 9 Memory circuitCPU EEPROMFLASHIC5IC6IC2Fig. 10 Clock diagramIC406CODECIC13FPGAIC8DSPIC5CPUIC14(2/3,3/3)9.216MHz9.216MHz18.432MHz18.432MHz18.432MHzIC12 X2VCXOIC14(1/3)