TH-K4AT/K4E
16
D34
AVR
constant-voltage
D35
Reverse current
Battery
prevention
D36
Reverse current
DC IN
prevention
D40
TX LED
Lights on TX
D41
BUSY LED
Lights on RX
D42-44
Key illumination
Key backlight illumination
D46,47
LED
D48,49
LCD illumination
LCD backlight illumination
LED
D60
Key type
detection
D61
UHF type
detection
D62-65
market code
detection
D69-72
Reverse current
Key matrix
prevention
D73
Voltage drop
D74
Over input
protection
D79,80
Limiter
D81
Reverse current
prevention
COMPONENTS DESCRIPTION
Ref. No.
Use/Function
Operation/Condition/Compatibility
Ref. No.
Use/Function
Operation/Condition/Compatibility
Q34
Q33 operation
On when charging
switch
Q35
DC IN detection H: DC IN detection
Q36
Ni-MH temperature
On when temperature detection is activated
detection
Q37
AF amplifier/
Lamp AVR
Q38
Q37 operation On when the speaker outputs the audio
switch
or lamp lights
Q41
5MS switch
On when 5MS is applied
Q47
TX/BUSY LED
switch
Q50
Key LED switch On when the key LED lights
Q51
LCD LED
On when the LCD LED lights
switch
Q52
Beat shift
switch
Q53
5R/5MV switch On when 5R or 5MV is applied
Q55
5T switch
On when 5T is applied
Q56
Speaker mute
switch
Q57
5C switch
On when 5C is applied
Q58
Q12 gate
Off when High power is selected
voltage switch
D1-4
VCO frequency
control
D5
Frequency shift
D6
VCO modulation
D7
Speed up
Ripple filter
D8
RF switch
On TX
D9
RF switch
On RX
D10-13
Antenna switch On TX
D14
Reverse current
APC reference voltage
prevention
D15
APC output
voltage limiter
D16
PLL lock detection
D18-21
RX BPF tuning
D22
MIC mute
control
D24
VOX detection
rectification
D25
Speaker mute
speed up
D26
C246 discharge
D27
MIC ALC
rectification
D30
Reverse current
Charge current
prevention
D31
Constant-current
Constant-current charge
circuit
D32
Reverse current
DC IN
prevention
D33
Reverse current
Battery
prevention