Icom IC-756PROII Service Manual page 18

3-7-4 INPUT EXPANDER ALLOCATIONS
(1) DISPLAY board; IC411
Pin Port
number name
Input port for the [RIT], [∆TX] and
1 KI4
[CLEAR] switches.
Input port for [UP] and [DN] switches
5 MUDK
of the connected microphone.
Input
12 KI3
[CHANGE], [V/M] and [M/S] switches.
Input port for the [TUNER], [MONI-
13 KI0
TOR], [NB] and [NR] switches.
Input ports for the multi-function
14, 15 KI1, KI2
switches.
(2) MAIN-A unit; IC3652
Pin Port
number name
11 CTFL Input port transmission status for CW
12 RTDT Input port for RTTY decode data.
Input port for the KEY signal from the
13 EKEY connected AH-3.
Low : While tuning or tune NG
Input port for AH-3 connection detec-
14 TCON tion.
High: When AH-3 is connected.
Input port for interrupting signal
16 VINT
from audio recoder.
Input port for address clock signal
17 VRAC
from audio recoder.
Input port for busy signal from the
18 SBSY installed UT-102 SPEECH SYNTHE-
SIZER.
3-7-4 OUTPUT EXPANDER ALLOCATIONS
(1) PLL unit; IC1
Pin Port
number name
Outputs strobe signals to DDS IC
4 PST1
(IC101) for the 1st LO PLL A circuit.
Outputs strobe signals to PLL IC
5 PST2
(IC381) for the 1st LO PLL A circuit.
Outputs strobe signals to DDS IC
PST3
6
(IC401) for the 1st LO PLL B circuit.
Outputs strobe signals to PLL IC
7 PST4
(IC681) for the 1st LO PLL B circuit.
Outputs strobe signals to DDS IC
12 PST5
(IC701) for the 3rd LO PLL circuit.
Outputs strobe signals to PLL IC
PST6
13
(IC901) for the S2 LO PLL circuit.
Outputs strobe signals to DDS IC
14 PST7
(IC801) for the S3 LO PLL circuit.
Description
port for the [D-WATCH],
Description
Description
(2) PLL unit; IC101
Pin Port
number name
66 MAKS
68 PAMT
70 PAFS
71 VA4S
VA3S
73
74 VA2S
75 VA1S
(3) PLL unit; IC401
Pin Port
number name
PBMT
68
70 PBFS
71 VB4S
73 VB3S
VB2S
74
VB1S
75
3 - 12
Description
Outputs the marker mute switch (IC192)
control signal.
High : When the [MARKER] is ON and
receiving.
Outputs LO mute switch (Q361) control
signal. Low : Muted
Outputs bandpass filter select switch
(Q351) control signal.
High : When less than 8 MHz is dis-
played on the main band.
Outputs the LO switch (Q121) control
signal.
High : While 45.0–60.0 MHz band is
displayed on the main band.
Outputs the LO switch (Q122) control
signal.
High : While 20.0–44.999999 MHz
band is displayed on the main
band.
Outputs the LO switch (Q123) control
signal.
High : While 8.0–19.999999 MHz band
is displayed on the main band.
Outputs the LO switch (Q126) control
signal.
High : While 0.03–7.999999 MHz band
is displayed on the main band.
Description
Outputs LO mute switch (Q661) control
signal. Low : Muted
Outputs bandpass filter select switch
(Q651) control signal.
High : When less than 8 MHz is dis-
played on the main band.
Outputs the LO switch (Q421) control
signal.
High : While 45.0–60.0 MHz band is
displayed on the main band.
Outputs the LO switch (Q422) control
signal.
High : While 20.0–44.999999 MHz
band is displayed on the main
band.
Outputs the LO switch (Q423) control
signal.
High : While 8.0–19.999999 MHz band
is displayed on the main band.
Outputs the LO switch (Q426) control
signal.
High : While 0.03–7.999999 MHz band
is displayed on the main band.