Receiver Adjustment - Icom IC-R8500 Service Manual

5-3
RECEIVER
ADJUSTMENT
ADJUSTMENT ADJUSTMENT
CONDITIONS
MEASUREMENT
VALUE
ADJUSTMENT
POINT
UNIT
LOCATION
UNIT
ADJUST
PIN
ATT
1
• Displayed
freq.
:
14.10000
MHz
•
Mode
;
USB
•
Receiving
RF-A
Connect a
digital mulli-
meter
to
CPI
.
1.7
V
RF-A R63
HF
SENSITIVITY
• Displayed
freq.
:
14.09850
MHz
•
Mode
:
USB
*[10dB]
:ON
•
[AGC]
;
Fast
•
Conned
an
SSQ
to
(he
antenna connec*
tor lor 0.1 -
30
MHz
(50
0
ANT) and
set
as:
Frequency
:
14.10000
MHz
Level
:
0.56
uV(-
112
dBm)
Modulation
:
OFF
• Receiving
Rear
panel
Connect an
AC
volt-
meter
to
the
(EXT SP]
with
an
80
load.
Maximum
oulpul
level
RF-A
Adjust
In
sequence
L65,
Lea
L63, L62
2
•
Set
an
SSG
output
level:
OFF
•
Receiving
Minimum
output
level
R77
1ST MIXER
BIAS
VOLTAGE
1
• Otsplaycd
freq.
;
173.00000
MHz
• Disconnect
J4.
•
Receiving
RF-B
Connect
a
digital multi-
meter
to
both terminals
of
R91.
0.2
V
RFB
RI09
HPF
SHIFT
VOLTAGE
1
•
Displayed
freq.
:
1300.00000
MHz
•
Mode :FM
• Receiving
CONV
Conned
a
digital
multi-
melerto CP2.
14.5
V CONV
RS5
2 • Displayed
freq.
:
1
100.00000
MHz
•
Receiving
3.0V
+1.0V
Verify
NOTE:
Before adjusting
WFM
SENSITIVITY. 5-4 RF-B
6PF TUNED VOLTAGE ADJUSTMENT
must be performed.
WFM
SENSITIVITY
• Displayed
freq.
:
173.02000
MHz
•
Mode
:
WFM
•
Connect an
SSG
to
the
antenna connec-
tor for
30-2000
MHz
and
set as:
Level
;
1
mV* (-47 dBm)
Modulation
:
1
kHz
Deviation
:±75kHz
• Receiving
MAIN Connect a
digital multi-
meter
to
CPI.
2.5
V
MAIN
C37
2
3
•
Set an
SSG
level as:
3.2 uV*
(
- 97 dBm)
• Receiving
Connect a
digital multi-
meter
to
CP4.
Minimum
voltage
Adjust
L7.
L8, L9.
L10
repeatedly
Connect
a
digital
multi-
meter
to
CPI
.
2.5
V
C37
FM
SENSITIVITY
•
Displayed
freq.
:
173.02000
MHz
•
Mode
;
FM
•
Connect an
SSG
to the
antenna connec-
tor lor
30-2000
MHz
and
set as:
Level
:3.2uV*(-97dBm)
Modulaiion
.
1
kHz
Deviation
;
z
5
kHz
• Receiving
Front
panel
S-meter
Maximum
level
MAIN
Adjust
in
repeatedly
L14,
L17
L22.
L25
126
1ST
IF
NOTCH
•
Displayed
freq.
:
78B.60000
MHz
•
Mode
;
FM
•
Connect an
SSQ
to
ihe
antenna connec-
tor tor
30-2000
MHz
and
set as:
Frequony
:
810.00000
MHz
Level
:
32
mV*
(-17 dBm)
Modulation
:
OFF
• Receiving
Front
panel
S-meter
Minimum
level
MIX
LI
5
*This output
level
cl a standard
signal generator (S$Q)
i$
Indicated
as
SSG's open
circuit.
5-3