Description Of Components - Kenwood TK-280 Service Manual

TK-280
DISPLAY UNIT (X54-3210-12)
Ref. No. Use/Function
IC300 IC
IC301 IC
Q300 FET
Q301 FET
Q302 Transistor
Q303 Transistor
Q304 Transistor
Q305 Transistor
Q306 Transistor
Q307 Transistor
Q308 FET
Q309 Transistor
Q310 FET
D300 Zener diode Surge absorption
D301 LED
D302 Diode
D303 Zener diode Voltage reference
D304 Diode
D305~310 LED
D315~318 Diode
D319~321 Zener diode Surge absorption
TX-RX UNIT (X57-6192-70)
Ref. No. Use/Function
IC1,2 IC
IC3 IC
IC4 IC
IC5 IC
IC6 IC
IC7 IC
IC8 IC
IC9 IC
IC10 IC
IC11 IC
IC12 IC
IC13 IC
IC14 IC
IC16 IC
IC17 IC
IC18 IC
IC19 IC
IC20 IC
IC21,22 IC
IC23 IC
IC24 IC
IC25 IC
Q1 Transistor
Q2 FET
Q3 Transistor
Q4 Transistor
Q5 FET
Q6 Transistor
32

DESCRIPTION OF COMPONENTS

Operation/Condition
Audio power amplifier
Counter /Key scan
DC switch / INT MIC on/off
DC switch
DC switch / LED (Red) driver
DC switch / LED (Green) driver
DC switch
Current driver / Audio amp AVR
DC switch
Current driver / LCD back light LED AVR
DC switch / SP INT/EXT
Temperature compensation
Mute switch
LED / Red, Green
Quick discharge /AF mute
Voltage reference
LCD back light
Reverse current prevention
Operation/Condition
Buffer amplifier
Voltage detector / Reset
Buffer amplifier
Voltage regulator / 5M
Voltage regulator / 5V
Buffer amplifier
D/A converter (Adjustment)
Voltage regulator / 5C
Active filter / For HSDout
Active filter / For LSDin
FM IF system
Audio processor
PLL system
DTMF decoder
Flash memory
Active DBM
Microprocessor
EEPROM
Shift register / Output expander
Comparator (APC)
Analog switch
Active filter
Switch
DC switch / 5R
DC switch / 5T
Noise amplifier / Squelch
DC switch / Save
nd
2 IF W/N switch sets to on when Narrow
Ref. No. Use/Function
nd
Q7 Transistor 2 IF W/N switch sets to on when Wide
Q8 Transistor Ripple filter
Q9 Transistor DC switch / W/N audio amplitude adjust
Q10 Transistor AF mute switch
Q11 FET Mute switch
Q12 Transistor IF amplifier
Q13 FET Mute switch / MIC line mute
Q14 FET DC switch
Q15 FET DET mute
Q16 Transistor PLL IC fin amplifier
Q17 FET Mute switch / MIC line mute
Q18 Transistor Buffer amplifier
Q19 Transistor Clock frequency shift
Q20 Transistor RF amplifier / TX driver
Q21 FET DC switch
Q22 Transistor DC switch
Q23 FET DC switch
Q24 FET RF amplifier
Q25 Transistor DC switch
D1 Diode Reverse protection
D2 Diode Overload protection
D3 Diode Reverse current protection
D4 Diode Noise detection
D5 Diode RF switch (2
D6 Diode Current steering
D7 Diode RF switch (2
D8 Diode Voltage clamp
D9 Diode TX/RX switch
D10 Diode Overload protection
D11 Diode Speed up
D12,14 Diode ANT switch
D16,17 Diode Varactor tuning
D18,19 Diode Surge absorption
D20,21 Diode Varactor tuning
D22 Diode ANT switch
D23 Diode TX/RX switch
D24 Diode Voltage drop
D401 Diode ANT switch
D402 Diode Discharge
SUB UNIT (X58-4580-10)
Ref. No. Use/Function
Q1 FET DC switch
Q2,3 FET VCO oscillation
Q4 Transistor DC switch
Q5 Transistor RF Buffer amplifier
D1-D8 Diode Frequency control
D9 Diode TX modulation
Operation/Condition
nd
IF wide/narrow)
nd
IF wide/narrow)
Operation/Condition