Relay Controller (Rxpll-B Unit; Ic1701); Relay Controller (Rxpll-B Unit; Ic1702); Buffer Ic (Main Unit; Ic291); Buffer Ic (Main Unit; Ic311) - Icom IC-7800 Service Manual

3-7-18 RELAY CONTROLLER (RXPLL-B UNIT; IC1701)

Pin Port
number name
Outputs the HF band's pre-amplifier 2
control signal for the RX-B circuit.
7 HFOFB
High : The pre-amplifiers are OFF.
Outputs the 50 MHz band's pre-
amplifier 1 control signal for the RX-B
11 VP1B
circuit.
High : The pre-amplifier1 is ON.
Outputs the HF band's pre-amplifier 2
control signal for the RX-B circuit.
12 HP2B
High : The pre-amplifier 2 is ON.
Outputs the HF band's pre-amplifier 1
control signal for the RX-B circuit.
13 HP1B
High : The pre-amplifier 1 is ON.
Outputs the 50 MHz band's pre-
amplifier control signal for the RX-B
14 VPOFB
circuit.
High : The pre-amplifier is OFF.

3-7-19 RELAY CONTROLLER (RXPLL-B UNIT; IC1702)

Pin Port
number name
Outputs the 1st IF control signal for
the RX-B circuit.
4 HSEL
High : While receiving on HF band.
Outputs the 1st IF control signal for
the RX-B circuit.
5 VSEL
High : While receiving on 50 MHz.
Outputs 1st IF filter (FI1401) select
signal for the RX-B circuit.
6 IFW
High : Select 16 kHz IF filter.
Outputs 1st IF filter (FI1402) select
signal for the RX-B circuit.
7 IFN
High : Select 6 kHz IF filter.
Outputs 1st IF filter (FI1403) select
signal for the RX-B circuit.
14 IFNN
High : Select 3 kHz IF filter.
Description
Description
3 - 22

3-7-20 BUFFER IC (MAIN UNIT; IC291)

Pin Port
number name
Outputs the transmit signal switching
signal.
12 TRVSM
High : The transverter is ON.
Outputs the SCOPE 3rd LO muting
signal.
13 SMUT
High : While muting.
Outputs the scope IF signal switching
signal.
14 SSB
High : Input from the RX-B circuit.
Outputs the scope IF signal switching
signal.
15 SSA
High : Input from the RX-A circuit.
Outputs the transmitting monitor
control signal.
16 MONS
High : Transmitting monitor is ON.
Outputs modulation input signal
control signal.
17 MCPS
High : Input from the microphone or
Outputs the microphone mute control
signal.
18 MMUT
High : While muting.

3-7-21 BUFFER IC (MAIN UNIT; IC311)

Pin Port
number name
11 FMS Outputs FM mode select signal.
Outputs mode selecting signal other
12 UNSB
than SSB and AM modes.
Outputs AF signals select signal.
High : While outputs AF signals to
13 B_AFA
Outputs AF signals select signal.
High : While outputs AF signals to
14 A_AFA
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.
15 SPON
High : While no headphones are
Outputs phone L/R mixer control
signal.
16 PMIX
High : While mixing.
Outputs AF signal selecting signal
from the MAIN pin or the SUB pin of
17 MAFS
[MIC] jack.
High : The SUB pin is selected.
Outputs receiver circuits switch signal
while split operating.
18 CROSS
High : Set to [MAIN] to B-channel.
Description
ACC jack.
Description
the ACC-B connector.
the ACC-A connector.
connected.
: Set to [SUB] to A-channel.