4 - 9
Description
The 13.8V external DC power from the power
connector.
The same voltage as the HV line which is con-
trolled by the VCC regulator circuit (MAIN unit;
Q2001). When the [POWER] switch is pushed,
the CPU outputs control signal to the power
switch controller (Q2003) to turn the circuit ON.
Common 5 V for the CPU converted from the HV
line by the 5V regulator circuit (IC2002). The volt-
age line is also applied to the CPU when IC-
2720H is power OFF.
Common 8 V converted from the VCC line at the
+8 regulator circuit (IC2003).
Common 5 V produced from the 5 V line by the
+5 regulator circuit (Q2002, D2048). The output
signal is applied to the PTT detector (Q2005),
mic amplifier (IC2014, Q2028), etc.VHF transmit.
8 V produced from the 8V line at the VT8 regula-
tor circuit (Q9, Q11).
UHF transmit 8V produced from the 8V line at the
UT8 regulator circuit (Q10, Q12).
VHF and UHF transmit 8 V produced from the 8
V line at the VUT8 regulator circuit (Q13, D1).
The output voltage is applied to the buffer ampli-
fier (Q38), pre-amplifier (Q16) and pre-driver
(Q21).
Receive 5 V produced from the 5VS line at the
L_R5 regulator circuit (Q1000). The output volt-
age is applied to the AM detector for left side dis-
play (Q1014, Q1017).
Receive 5 V produced from the 5VS line at the
R_R5 regulator circuit (Q1002). The output volt-
age is applied to the AM detector for right side
display (Q1022, Q1025).
Receive 5 V produced from the 5VS line at the
L_AM5 regulator circuit (Q1006). The output volt-
age is applied to the IF amplifier (Q1040) and FM
IF IC (IC1001) for left side display.
Receive 5 V produced from the 5VS line at the
R_AM5 regulator circuit (Q1005). The output
voltage is applied to the IF amplifier (Q1041) and
FM IF IC (IC1004) for right side display.
Receive 5 V produced from the 5VS line at the
L_R5 regulator circuit (Q1). The output voltage is
applied to the RF amplifier (Q29) for left side dis-
play’s 144 MHz bandpass filter.
Receive 5 V produced from the 5VS line at the
R_R5 regulator circuit (Q2). The output voltage is
applied to the RF amplifier (Q30) for right side
display’s 144 MHz bandpass filter.
Line
HV
VCC
5V
8V
5VS
VT8
UT8
VUT8
L_AM5
R_AM5
L_R5
R_R5
L140_R5
R140_R5
Description
Receive 5 V produced from the 5VS line at the
R_AM5 regulator circuit (Q3). The output voltage
is applied to the RF amplifier (Q31) for left side
display’s 220 MHz bandpass filter.
Receive 5 V produced from the 5VS line at the
L_AM5 regulator circuit (Q4). The output voltage
is applied to the RF amplifier (Q32) for right side
display’s 300 MHz bandpass filter.
Receive 5 V produced from the 5VS line at the
R_R5 regulator circuit (Q5). The output voltage is
applied to the RF amplifier (Q19) for right side
display’s 430 MHz bandpass filter.
Receive 5 V produced from the 5VS line at the
R_AM5 regulator circuit (Q6). The output voltage
is applied to the RF amplifier (Q20) for left side
display’s 430 MHz bandpass filter.
Receive 5 V produced from the 5VS line at the
L_AM5 regulator circuit (Q8). The output voltage
is applied to the RF amplifier (Q18, Q35) for right
side display’s 910 MHz bandpass filter.
Common 8 V produced from the 8 V line by the
+8 regulator circuit (Q1023). The output voltage
is applied to the VCO circuit (RF unit; Q6,
D3–D5) and buffer amplifier (RF unit; Q8).
Common 5 V converted from the HV line by the
+5 regulator circuit (CONTROL unit; IC3). The
output voltage is applied to the buffer amplifier
(CONTROL unit; Q2) and reset circuit (CON-
TROL unit; IC2).
Line
L220_R5
L300_R5
R400_R5
L400_R5
R800_R5
L_VCO8
CPU5
Description
Common 8 V converted from the VCC line at the
+8 regulator circuit (MAIN unit; IC2003). The out-
put voltage is applied to the filter switch (IC2),
loop filter (Q2, Q3, D2) and buffer amplifier (Q8).
Common 5 V produced from the 5 V line by the
+5 regulator circuit (MAIN unit; Q2002, D2048).
The output voltage is applied to the PTT IC (IC1)
and regulator circuit (Q9).
Common 8 V produced from the 8 V line by the
+8 regulator circuit (Q1023). The output voltage
is applied to the VCO circuit (RF unit; Q6,
D3–D5) and buffer amplifier (RF unit; Q8).
Line
8V
5VS
L_VCO8
4-4-2 MAIN UNIT VOLTAGE LINE
MAIN UNIT VOLTAGE LINE–Continued
4-4-3 VCO UNIT VOLTAGE LINE
