Kenwood TK-790 Service Manual

Also see for FleetSync TK-790: Specifications Instruction manual Specifications Instruction manual

36TK-790/(B)/H(B)General : TK-790/(B)Ref. No. Use/Function Operation/ConditionIC1 Power amplifierGeneral : TK-790H(B)Ref. No. Use/Function Operation/ConditionIC1 TX drive amplifierQ6,7 Final amplifierFinal Unit (X45-3560-10) : TK-790H(B)Ref. No. Use/Function Operation/ConditionQ1 DC amplifier APC controllerQ2 DC switchQ3 APC controllerQ4 DC amplifier APC controllerQ5 APC comparator APC controllerQ8 TX/RX switch On when RXQ9 TX/RX switch ON when RXQ10,11 DC switchD1 Forward waverectificationD2 Reflected waverectificationD3 CombinerD4,5 Surge absorptionD6 Voltage referenceD7 Protect of reverseconnectionTX-RX Unit (X57-5610-XX) (A/3)-10 : TK-790/(B) K -11 : TK-790(B) K2 -12 : TK-790H(B) KRef. No. Use/Function Operation/ConditionIC101 FM IC 1, 2 : Oscillator (45.305MHz)3 : Mixer output 4 : Vcc5 : IF input (455kHz)7 : Noise filter output8 : Noise filter input9 : DET output (AF OUT)10 : Quad input12 : RSSI output16 : Input (44.85MHz)IC201 Shift registerIC202 AVR Input : 8V Output : 5VRef. No. Use/Function Operation/ConditionIC203 AVR Input : SB Output : 9VIC301 PLL IC 1 : CP 2 : DT 3 : EP4 : Vss 5 : Fin 7 : Vcc8 : REFin (16.8MHz)14 : Charge pump output18 : UL (“H” when lock)20 : VDD (5V)Q101 1st amplifier RX frequencyQ102 IF amplifier 44.85MHzQ104 Mix local amplifier (RX frequency + 44.85)MHzQ105 DC switch ON when wideQ106 DC switch On when narrowQ107 IF amplifier 44.85MHzQ108 DC switch On when wideQ109 SQL amplifier (Noise amplifier)Q201 TX pre-drive amplifierQ202 8T switch 8V when TXQ203 8T switch On when TXQ204 TX pre-drive amplifierQ205 8R switch On when RXQ206 8R switch 8V when RXQ301 Ripple filter 8CLQ302 Ripple filter 9CLQ303,304 Loop filterQ305 OSC RX-VCOQ306 OSC TX-VCOQ307 DC switch On when TXQ308 DC switch On when RXQ309 DC switch Off when TXQ310 Buffer amplifierQ311,312 AmplifierD101 DC switch On when TXD102 BPF tuning Vari-cap tuningD103 Noise detectorD104,105 BPF tuning Vari-cap tuningD106~109 IF switch Wide/NarrowD201,202 TX pre-drive biasD301 Frequency controller TX-VCOD302 Frequency controller RX-VCOD303 Frequency controller TX-VCOD304 Frequency controller RX-VCOD305 ModulatorD306 RF switch TX/RXA101 DBMDESCRIPTION OF COMPONENTS