![background image](http://html.mh-extra.com/html/icom/ic-7800/ic-7800_service-manual_612345034.webp)
3 - 22
3-7-18 RELAY CONTROLLER (RXPLL-B UNIT; IC1701)
7 HFOFB
Outputs the HF band’s pre-amplifier 2
control signal for the RX-B circuit.
High : The pre-amplifiers are OFF.
11 VP1B
Outputs the 50 MHz band’s pre-
amplifier 1 control signal for the RX-B
circuit.
High : The pre-amplifier1 is ON.
12 HP2B
Outputs the HF band’s pre-amplifier 2
control signal for the RX-B circuit.
High : The pre-amplifier 2 is ON.
13 HP1B
Outputs the HF band’s pre-amplifier 1
control signal for the RX-B circuit.
High : The pre-amplifier 1 is ON.
14 VPOFB
Outputs the 50 MHz band’s pre-
amplifier control signal for the RX-B
circuit.
High : The pre-amplifier is OFF.
Pin
Port
Description
number
name
3-7-19 RELAY CONTROLLER (RXPLL-B UNIT; IC1702)
4 HSEL
Outputs the 1st IF control signal for
the RX-B circuit.
High : While receiving on HF band.
5 VSEL
Outputs the 1st IF control signal for
the RX-B circuit.
High : While receiving on 50 MHz.
6 IFW
Outputs 1st IF filter (FI1401) select
signal for the RX-B circuit.
High : Select 16 kHz IF filter.
7 IFN
Outputs 1st IF filter (FI1402) select
signal for the RX-B circuit.
High : Select 6 kHz IF filter.
14 IFNN
Outputs 1st IF filter (FI1403) select
signal for the RX-B circuit.
High : Select 3 kHz IF filter.
Pin
Port
Description
number
name
3-7-20 BUFFER IC (MAIN UNIT; IC291)
12 TRVSM
Outputs the transmit signal switching
signal.
High : The transverter is ON.
13 SMUT
Outputs the SCOPE 3rd LO muting
signal.
High
:
While
muting.
14 SSB
Outputs the scope IF signal switching
signal.
High : Input from the RX-B circuit.
15 SSA
Outputs the scope IF signal switching
signal.
High : Input from the RX-A circuit.
16 MONS
Outputs the transmitting monitor
control signal.
High : Transmitting monitor is ON.
17 MCPS
Outputs modulation input signal
control signal.
High
:
Input from the microphone or
ACC jack.
18 MMUT
Outputs the microphone mute control
signal.
High
:
While
muting.
Pin
Port
Description
number
name
3-7-21 BUFFER IC (MAIN UNIT; IC311)
11
FMS
Outputs FM mode select signal.
12 UNSB
Outputs mode selecting signal other
than SSB and AM modes.
13 B_AFA
Outputs AF signals select signal.
High
:
While outputs AF signals to
the ACC-B connector.
14 A_AFA
Outputs AF signals select signal.
High
:
While outputs AF signals to
the ACC-A connector.
15 SPON
O u t p u t s t h e i n t e r n a l s p e a ke r
switching signal.
High
:
While no headphones are
connected.
16 PMIX
Outputs phone L/R mixer control
signal.
High
:
While
mixing.
17 MAFS
Outputs AF signal selecting signal
from the MAIN pin or the SUB pin of
[MIC] jack.
High : The SUB pin is selected.
18 CROSS
Outputs receiver circuits switch signal
while split operating.
High : Set to [MAIN] to B-channel.
: Set to [SUB] to A-channel.
Pin
Port
Description
number
name