Kenwood TM-631A Service Manual page 24

TM-631A
DESCRIPTION
OF
ELEMENTS
Use/Function
Operation/Condition/Compatibility
Components
Q17 Phase locked loop voltage amplifier
On
reception 127.1
~131.095
MHz
Q18
PLL
output amplifier
On
transmit
144~147.995
MHz
Q19, 20
Radio-frequency amplifier
Activates when
transmitting
Q21
PLL
reference oscillator
12.8 MHz
D1
Reverse current protection
D4~8
Varicap
tuning
D9 Reverse current protection
D10 S-meter detection
D11,12 Reverse current protection
D13 PLL output switch
D14 Q20
idling
144 MHz PLL
unit (X58-3670-10)
Components
Use/Function
Operation/Condition/Compatibility
@ VCO
input
When receiving: 127.1
~131.095
MHz
When transmitting:
144~147.995
MHz
IC1
PLL
10
At low level when transmitting
14
At
high level
when unlocked
23
Reference oscillator
inout
12.8 MHz
Q1,2
LPF
Q3
Transmission select switch Turns
ON at the
moment when transmission starts
When receiving: 127.1
~131.095
MHz
04 VCO
output amplifier
When transmitting:
144~147.995
MHz
Q5
Transmission select switch Turns OFF when transmit
Q102
Receive VCO
When receiving:
127.1~131.095
MHz
Q101
When transmitting:
144~147.995
MHz
When receiving: 127.1
~131.095
MHz
Q102 Receive VCO switch
When transmitting:
144~147.995
MHz
Turns
ON
when receive
Q103 Receive VCO
output buffer 127.1
131.095 MHz
Q104 Transmit
VCO
144
~
147.995
MHz
Q105 Transmit VCO switch Turns
ON
when transmit
Q106
Transmit
VCO
output buffer
144~147.995
MHz
D101
Varicap
for
transmission modulation
D102 VCO voltage
control
D103
VCO voltage
control Transmit modulation varicap transmit
D104 VCO voltage
control
Transmit modulation varicap transmit
23
TM-631A
DESCRIPTION
OF
ELEMENTS
Use/Function
Operation/Condition/Compatibility
Components
Q17 Phase locked loop voltage amplifier
On
reception 127.1
~131.095
MHz
Q18
PLL
output amplifier
On
transmit
144~147.995
MHz
Q19, 20
Radio-frequency amplifier
Activates when
transmitting
Q21
PLL
reference oscillator
12.8 MHz
D1
Reverse current protection
D4~8
Varicap
tuning
D9 Reverse current protection
D10 S-meter detection
D11,12 Reverse current protection
D13 PLL output switch
D14 Q20
idling
144 MHz PLL
unit (X58-3670-10)
Components
Use/Function
Operation/Condition/Compatibility
@ VCO
input
When receiving: 127.1
~131.095
MHz
When transmitting:
144~147.995
MHz
IC1
PLL
10
At low level when transmitting
14
At
high level
when unlocked
23
Reference oscillator
inout
12.8 MHz
Q1,2
LPF
Q3
Transmission select switch Turns
ON at the
moment when transmission starts
When receiving: 127.1
~131.095
MHz
04 VCO
output amplifier
When transmitting:
144~147.995
MHz
Q5
Transmission select switch Turns OFF when transmit
Q102
Receive VCO
When receiving:
127.1~131.095
MHz
Q101
When transmitting:
144~147.995
MHz
When receiving: 127.1
~131.095
MHz
Q102 Receive VCO switch
When transmitting:
144~147.995
MHz
Turns
ON
when receive
Q103 Receive VCO
output buffer 127.1
131.095 MHz
Q104 Transmit
VCO
144
~
147.995
MHz
Q105 Transmit VCO switch Turns
ON
when transmit
Q106
Transmit
VCO
output buffer
144~147.995
MHz
D101
Varicap
for
transmission modulation
D102 VCO voltage
control
D103
VCO voltage
control Transmit modulation varicap transmit
D104 VCO voltage
control
Transmit modulation varicap transmit
23