Kenwood NXR-710 Service Manual

Also see for NEXEDGE NXR-710: Instruction manual Instruction manual Instruction manual Instruction manual Instruction manual

NXR-710132-10. Other circuit■ EEPROMThe EEPROM (IC802) has a data capacity of 2Kbit. Itstores the tuning data in frequency adjustment.■ Temperature sensorThe temperature sensor (IC800) monitors temperaturearound the VCTCXO (X500).■ I/O expanderThe I/O expander IC (IC805) controls power sources, fan,analogue switches, and the transmit power control circuit.IC805 is controlled by the MCU which is in the Control unit(X53-449).■ Electronic volume control ICThe Electronic volume control IC (IC804) adjusts themodulating signal, center frequency of the front-end BPF,and the power of the RF final amplifier. IC804 is controlledby the MCU which is in the Control unit.3. Final unitThe RF final amplifier unit (X45-3920-10) amplifies thetransmitter power to a specified level.This unit consists of the following circuits:(1) Driver and Final power amplifier circuit(2) CM coupler circuit(3) Filter circuit(4) APC circuit(5) High temperature detector circuit(6) FAN action control circuit(7) AVR circuit3-1. Driver and Final power amplifier circuitThe transmit signal from the TX IN terminal CN1 of theFinal unit (X45-392) is amplified by Q1, Q2 and Q3, and ispassed to the final stage Q4. The signal amplified by thefinal stage Q4 passes through the CM coupler circuit andfi lter circuit, and is then fed to the antenna.80C_1Ripple FilterRipple FilterRipple Filter15V DC/DCIC701SWRXCQ700,Q701SWRXCQ705,Q706SWSBCSBQ702,Q703CN701+Bfrom Final unit(X45-392 A/3)+B,SBto Control unit(X53-449)3V AVRIC7043.3V AVRIC703Ripple Filter80C80C_2150C_1150C_280R5V AVRIC7008V AVRIC70250C50R30R33CCN700Fig. 11 AVR circuitFig. 12 Driver and Final power amplifier circuitCN801CN1PLIMFDT8TCFANASWCRAMPDC AMPIC202(A/2)TX ANTLPF CM couplerVcontREV DET FW DETAuto power control+B 80T80TFW DETD3PRE AMPIC201(A/2)Limiter AMPIC201(B/2)Drive AMPQ1Drive AMPQ2Final AMPQ4Drive AMPQ3Temp1TH201Buffer AMPIC202(B/2)REV DETD4CIRCUIT DESCRIPTION