Description Of Components - Kenwood TK-790 Service Manual

TK-790/ ( B
General : TK-790/(B)
Ref. No. Use/Function
IC1 Power amplifier
General : TK-790H(B)
Ref. No. Use/Function
IC1 TX drive amplifier
Q6,7 Final amplifier
Final Unit (X45-3560-10) : TK-790H(B)
Ref. No. Use/Function
Q1 DC amplifier
Q2 DC switch
Q3 APC controller
Q4 DC amplifier
Q5 APC comparator
Q8 TX/RX switch
Q9 TX/RX switch
Q10,11 DC switch
D1 Forward wave
rectification
D2 Reflected wave
rectification
D3 Combiner
D4,5 Surge absorption
D6 Voltage reference
D7 Protect of reverse
connection
TX-RX Unit (X57-5610-XX) (A/3)
-10 : TK-790/(B) K -11 : TK-790(B) K2 -12 : TK-790H(B) K
Ref. No. Use/Function
IC101 FM IC
IC201 Shift register
IC202 AVR
36
) /H ( B )

DESCRIPTION OF COMPONENTS

Operation/Condition
Operation/Condition
Operation/Condition
APC controller
APC controller
APC controller
On when RX
ON when RX
Operation/Condition
1, 2 : Oscillator (45.305MHz)
3 : Mixer output 4 : Vcc
5 : IF input (455kHz)
7 : Noise filter output
8 : Noise filter input
9 : DET output (AF OUT)
10 : Quad input
12 : RSSI output
16 : Input (44.85MHz)
Input : 8V Output : 5V
Ref. No. Use/Function
IC203 AVR
IC301 PLL IC
Q101 1st amplifier
Q102 IF amplifier
Q104 Mix local amplifier
Q105 DC switch
Q106 DC switch
Q107 IF amplifier
Q108 DC switch
Q109 SQL amplifier
Q201 TX pre-drive amplifier
Q202 8T switch
Q203 8T switch
Q204 TX pre-drive amplifier
Q205 8R switch
Q206 8R switch
Q301 Ripple filter
Q302 Ripple filter
Q303,304 Loop filter
Q305 OSC
Q306 OSC
Q307 DC switch
Q308 DC switch
Q309 DC switch
Q310 Buffer amplifier
Q311,312 Amplifier
D101 DC switch
D102 BPF tuning
D103 Noise detector
D104,105 BPF tuning
D106~109 IF switch
D201,202 TX pre-drive bias
D301 Frequency controller
D302 Frequency controller
D303 Frequency controller
D304 Frequency controller
D305 Modulator
D306 RF switch
A101 DBM
Operation/Condition
Input : SB Output : 9V
1 : CP 2 : DT 3 : EP
4 : Vss 5 : Fin 7 : Vcc
8 : REFin (16.8MHz)
14 : Charge pump output
18 : UL ("H" when lock)
20 : VDD (5V)
RX frequency
44.85MHz
(RX frequency + 44.85)MHz
ON when wide
On when narrow
44.85MHz
On when wide
(Noise amplifier)
8V when TX
On when TX
On when RX
8V when RX
8CL
9CL
RX-VCO
TX-VCO
On when TX
On when RX
Off when TX
On when TX
Vari-cap tuning
Vari-cap tuning
Wide/Narrow
TX-VCO
RX-VCO
TX-VCO
RX-VCO
TX/RX