Icom IC-7800, Service Manual Addendum

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