Kenwood TM-271A Service Manual

TM-271A/271E
9
Display Unit (X54-3450-10)
Ref. No. Parts name Description
IC3 IC LCD controller
Q6 Transistor DC switch
Q9 Transistor LCD backlit switch
Q10 Transistor Key backlit switch
Q12 Transistor Brightness function switch
D2~4 LED Key backlit
D19~30 LED LCD backlit
D31 Diode Reverse connection protection
TX-RX Unit (X57-685X-XX)
Ref. No. Parts name Description
IC31 IC Voltage regulator (8C)
IC32 IC Voltage regulator (5C)
IC33 IC Voltage regulator (5M)
IC34 IC Voltage detector (reset)
IC35 IC Voltage detector (int)
IC66 IC EEPROM
IC101 IC CPU
IC161 IC Digital potentiometer
IC201 IC MIC amplifier / IDC
IC202 IC MIC amplifier / Splatter filter
IC203 IC Buffer amplifier / SUM amplifier
/ DC amplifier / 1/2 Vcc
IC204,205 IC Single analog switch
IC251 IC Audio filter
IC252 IC Audio amplifier
IC301 IC FM demodulation
IC401 IC PLL synthesizer
IC402 IC Divider (Hetero)
IC501 IC APC controller
Q31,32 Transistor DC switch (SB) / Active when power is on
Q33,34 Transistor DC switch (8R) / Active while RX
Q35,36 Transistor DC switch (8T) / Active while TX
Q61 Transistor Over voltage detection / Active when
PS voltage is more than 18V
Q86,87 Transistor Beat shift / Active while beat shift is on
Q201 Transistor AGC / MIC mute
Q251 Transistor Buffer amplifier / RX audio
Q252,253 FET AF mute / Active while AFM is H
Q254 Digital transistor AF mute / Active while SPM is H
Q255 Transistor AF mute / Active while AMPSW is H
Q301 Transistor Noise amplifier / SQL amplifier
Ref. No. Parts name Description
Q302 Transistor Buffer amplifier / 16.8MHz 3rd over tone
Q351 Transistor IF amplifier
Q352 FET Mixer
Q353 FET RF amplifier / LNA
Q354 Transistor PC/TV switch
Q402,403 Transistor Charge pump
Q404 Transistor RF amplifier / PLL F in
Q405 FET RX VCO
Q406 FET TX VCO
Q407 FET T/R switch
Q408 Transistor T/R switch
Q410 Transistor Buffer amplifier / Output of VCO
Q411 Transistor RF amplifier / Output of VCO
Q440 Transistor Lipple filter
Q501,502 Transistor RF amplifier / Drive stage
Q503 FET RF amplifier / Drive amplifier
Q504 FET RF amplifier / Final amplifier
D1 Diode Surge absorption / CM
D2 Diode Surge absorption / MIC key
D3 Diode Surge absorption / RXD
D4 Diode Surge absorption / PTT
D5 Diode Surge absorption / SQC
D6 Diode Surge absorption / PKS
D31 Diode Reverse connection protection
D32 Poly switch Current protection
D61,62 Diode Over voltage detection
D201 Diode OR gate / MIC mute, AGC
D202 Diode AGC
D251 Diode Limiter
D301 Diode Detection
D302,303 Diode IF switch (Wide/Narrow)
D351~354 Varicap RF BPF tuning
D401 Diode Ripple filter
D402 Diode Voltage dropped
D403,404 Varicap RX VCO
D405,406 Varicap TX VCO
D407 Varicap Modulation
D408 Diode Lipple filter
D409 Diode RF switch (TX/RX)
D501,502 Diode Temperature compensation
D503 Diode Voltage protection
D602,603 Diode ANT switch
D605 Diode ANT switch
D606,607 Diode APC voltage detect
D608 Diode Temperature compensation
COMPONENTS DESCRIPTION

Kenwood TM-271A Specifications

General

Brand	Kenwood
Model	TM-271A
Category	Transceiver
Language	English