Power Supply Circuits; Port Allocations - Icom IC-R8500 Service Manual

4-3
POWER
SUPPLY
CIRCUITS
4-3-1
VOLTAGE
LINES
Line Description
ADHV.
HV1
The
voltage
from an
AC
adaptor
(AD-55).
HV2
The
same
voltage as
the
ADHV
or
HV1
line
which
Is
controlled by the
(POWER)
switch.
DOUT
Common
12.5
V
converted from
the
HV2
line
by
the regulator
circuit
(MAIN
unit, IC22).
DCIN
The
same
voltage as the
DOUT
line
when
the
jumper connector
Is
connected
to
the
[DC
1
3.8
V],
or
the voltage from an
external
power
supply.
LHV1
The
same
voltage as the
DCIN
line
which
is
passed through the
Internal
fuse (MAIN
unit,
FI).
LHV2
The
same
voltage as the
LHVI
line
which
is
controlled
by
the
(POWER)
switch.
13.8
The same
voltage
as the
LHV2
line
which
is
passed through the switching
relay
(MAIN
unit,
RL1).
+8
Common
8
V
line
converted from the
1
3.8 line
by the 8
V
regulator circuit
(MAIN
unit,
IC23).
+5
Common
5
V
line
converted from the 13.8
line
by
the
5
V
regulator
circuit
(MAIN
unit,
IC17).
L+5
Common
5
V
line
converted from the
LHV2
line
by the
L+5
regulator
circuit
(MAIN
unit.
IC38).
+24
Common
24
V
line
converted from the 13.8
line
by the
DC-DC
convertor
circuit
{MAIN
unit,
Q51
.
Q52, L46)
and +24
regulator
circuit
(MAIN
unit,
IC25).
The
output voltage
is
applied to
the
CONV, RF-B
and
PLL
units.
-8
Common -8 V
line
converted from
the 13.8
line
by
the
DC-DC
convertor
circuit
(MAIN
unit,
Q51
,
Q52,
L46)
and -
8 regulator
circuit
(MAIN
unit,
IC26).
The
output voltage
is
applied to the
AGC
and
APF
circuits, etc.
+16
Common
1
6
V
line
converted from the +24
line
by
the
+16
regulator
circuit
(PLL
unit,
Q34, D20).
+8
Common
8
V
line
converted from
the 13.8
line
by the
+8
regulator
circuit
(PLL
unit.
IC17).
+5
Common
5
V
line
converted from the
1
3.8
line
by the
+5
regulator
circuit
(PLL
unit.
IC16).
D+5
Common
5
V
line
converted from the
1
3.8 line
by the
D+5
regulator
circuit
(PLL
unit,
1C24).
MI5V
Receive 5
V
line
tor
RF
signals
above 30 MHz,
which
is
converted from the
+5
line
by the
MI5V
regulator
circuit
(MAIN
unit,
Q35. Q36, D55).
The
output voltage
Is
applied
to
the
LO
amplifier
circuit(s) in
the
RF-B and MIX
units.
Hf5V
Receive
5
V
line for
RF
signals
below 30
MHz.
which
is
converted from the +5
line
by
the
HF5V
regulator
circuit
(RF-A
unit.
Q13, Q17).
The
output voltage
Is
applied
to
the
LO
amplifier
circuits
(RF-A
unit,
IC1
,
IC2).
4-4
PORT ALLOCATIONS
4-4-1
CPU
(MAIN
UNIT,
IC33)
Pin
number
Port
name
Description
1
RES
Input port
for
reset
signal.
9
POC
Outputs the switching
relay
(RL1
)
con-
trol
signal.
10
MRXD
Input port for the
sub
CPU
(DISP
unit,
IC1) data
signal.
11
MTXD
Outputs data
signal to
the sub
CPU
(DISP
unit,
IC1).
Input port for
optional
speech
synthe-
13
VBSY
sizer
busy
signal.
"High"
:
During
speech
19 Mdat Outputs
serial
data
signal.
20
Mck
Outputs
serial
clock
signal.
21
VSTB
Outputs
strobe signals
to
an
optional
speech
synthesizer.
MST2
Outputs strobe signals
to
the output
22-24 MST1
expander
ICs
in
the
MAIN
unit
(IC15,
MST3
IC16, IC18).
25.
26
STBA
Outputs strobe signals the output ex-
STBC
pander ICs
In
the
RF-A
unit (ICS, IC4).
27
STBB
Outputs strobe
signals
to
the output^
expander
1C
in
the
CONV
unit (ICIO).
28
STBE
Outputs strobe signals
to
the convertor
PLL
circuit
(CONV
unit.
IC4).
30
L1AD
Input port for 1st
LO PLL
lock voltage.
32
SMAD
Input port for
S-meter
signal.
33
CMAD
Input port for center indicator signal.
34
NOAD
Input port
for
noise
level signal.
35
STOP
Input port for
scan stop
signal.
37
LVDA
Outputs tunable
bandpass
filter
control
signal.
39
VSC
Input port
for
VSC
detected
signal.
40
BEEP
Outputs
beep
audio
signals.
41
Pdat
Outputs
serial
data
signal
for
the
PLL
circuit
46
AFDA
Outputs amplifying gain control signal
to the
AF
pre-amplifier
circuit
(IC20).
48
A15
Input port for
initial
matrix.
49-55 A14-A8
Address bus
lines for
the
EEPROM
(IC34).
57-64 A7-A0
Address bus
lines for
the
EEPROM
(1C34).
65-68 DO-D3
Data bus
lines for the
EEPROM
(IC34).
69-71
D4-D6
Output
port
for
initial
matrix.
72 D7
Data bus
line for
the
EEPROM
(1C34).
78
TXD
Outputs Cl-V
control signals.
79
RXO
Input port for
Cl-V
control signals.
4-8