Kenwood TK-5810H Service Manual

Also see for FleetSync TK-5810(H): Instruction manual Specifications Service manual Instruction manual

Contents

7TK-5810H(B)CIRCUIT DESCRIPTION1-1. Final Amplifier Circuit (From Power module toAntenna output): TK-5810H (B)The transmit signal from the TX terminal (CN1) of the finalunit (X45-380) is amplified by the power module (IC1).The signal amplified by the power module is divided intotwo signal, and further is amplified by the final amplifier(Q1,Q2). The each signal from Q1 and Q2 is combined.The combined signal passes through the antenna switch(D5, D6, D7, D8, D15, D16), CM coupler and low-pass filter,then it is fed to the antenna.CM coupler is a line for detecting forward wave andreflected wave.FINAL UNIT (X45-380)ANTD3 D5,D6,D7D8,D15,D16APCD2TX(CN1)LPFFWDDETREFLDETANTSWPOWERMODULE+B8TPC8TVR1IC1IC2+BFinal AMPQ2Final AMPQ1+BCMCOUPLERFig. 1 Final amplifier circuit: TK-5810H (B)Forward wave is detected by D2, and is converted intoDC voltage. The converted DC voltage is fed to the APCcomparator (IC2), and is compared with the PC voltage, thenis output from the OUT-B terminal (pin 7) of IC2 as an APCvoltage. The APC voltage controls the gate voltage of thepower module (IC1) and final amplifier (Q1,Q2), and keepstransmission output stable.If an abnormal antenna load is connected, reflected waveis detected by D3, and output voltage (DC voltage) is fed tothe APC comparator (IC2). The transmission output isreduced more as this DC voltage rises.1-2. Temperature Protection Circuit : TK-5810H (B)To prevent thermal destruction of the power module(IC1) and final amplifier (Q1,Q2), this circuit reduces APCvoltage when temperature of the power module (IC1) andfinal amplifier (Q1,Q2) rises.The CPU (IC703) detects temperature with thethermistor (TH1,TH3) and controls reference voltage to theAPC circuit.