Icom IC-7800 Service Manual Addendum page 365

3-7-11 RELAY CONTROLLER (BPF UNIT; IC402)
Pin Port
number name
Outputs the RX-B circuit bandpass fil-
ter group select signal.
6 HF50B
Low : While receiving on 30–60 MHz.
Outputs the RX-B circuit 12 dB atten-
uator control signal.
7 AT12B
High : The 12 dB attenuator is ON.
Outputs the RX-B circuit 6 dB attenu-
ator control signal.
8 AT6B
High : The 6 dB attenuator is ON.
Outputs the RX-B circuit 3 dB attenu-
ator control signal.
9 AT3B
High : The 3 dB attenuator is ON.
Outputs the RX-B circuit receive sig-
nals switch signal.
11 DWSPB
Low : The splitter function is ON.
Outputs the RX-B circuit mute control
signal.
12 RMUTB
Low : While the RX-B circuit is muting.
Outputs the RX-B circuit 50 MHz pre-
amplifier 2 control signal.
16 VPR2B
Low : The pre-amplifier2 is ON.
Outputs the RX-B circuit 50 MHz cor-
rection amplifier control signal.
17 VDWB
Low : The pre-amplifier 2 is ON
3-7-12 CONTROLLER IC (DIGISEL-A UNIT; IC4)
Pin Port
number name
6, X1A, Outputs the network serial reactance
7 X2A control signals.
Output the network I/O capacitance
8–11 S1A–S4A
control signals.
Output the network capacitance con-
12–17 C1A–C6A
trol signals.
3-7-13 CONTROLLER IC (DIGISEL-A UNIT; IC5)
Pin Port
number name
Output the network capacitance con-
6–10 C7A–C11A
trol signals.
Output the network reactance control
11–17 L1A–L7A
signals.
Description
(Receive on 50 MHz band).
Description
Description
3-7-14 CONTROLLER IC (DIGISEL-B UNIT; IC504)
Pin Port
number name
6, X1B,
7 X2B
8–11 S1B–S4B
12–17 C1B–C6B
3-7-15 CONTROLLER IC (DIGISEL-B UNIT; IC505)
Pin Port
number name
6–10 C7B–C11B
11–17 L1B–L7B
3-7-16 RELAY CONTROLLER (RXPLL-A UNIT; IC1701)
Pin Port
number name
7 HFOFA
11 VP1A
12 HP2A
13 HP1A
14 VPOFA
3-7-17 RELAY CONTROLLER (RXPLL-A UNIT; IC1702)
Pin Port
number name
4 HSEL
5 VSEL
6 IFW
7 IFN
14 IFNN
3 - 21
Description
Output the network serial reactance
control signals.
Output the network I/O capacitance
control signals.
Output the network capacitance con-
trol signals.
Description
Output the network capacitance con-
trol signals.
Output the network reactance control
signals.
Description
Outputs the HF band's pre-amplifier 2
control signal for the RX-A circuit.
High : The pre-amplifiers are OFF.
Outputs the 50 MHz band's pre-ampli-
fier 1 control signal for the RX-A cir-
cuit.
High : The pre-amplifier 1 is ON.
Outputs the HF band's pre-amplifier 2
control signal for the RX-A circuit.
High : The pre-amplifier 2 is ON.
Outputs the HF band's pre-amplifier 1
control signal for the RX-A circuit.
High : The pre-amplifier 1 is ON.
Outputs the 50 MHz band's pre-ampli-
fier control signal for the RX-A circuit.
High : The pre-amplifier is OFF.
Description
Outputs the 1st IF control signal for
the RX-A circuit.
High : While receiving on HF band.
Outputs the 1st IF control signal for
the RX-A circuit.
High : While receiving on 50 MHz.
Outputs 1st IF filter (FI1401) select
signal for the RX-A circuit.
High : Select 15 kHz IF filter.
Outputs 1st IF filter (FI1402) select
signal for the RX-A circuit.
High : Select 6 kHz IF filter.
Outputs 1st IF filter (FI1403) select
signal for the RX-A circuit.
High : Select 3 kHz IF filter.