Icom IC-910H, Service Manual

Page: 62 / 144

*This output level of a standard signal generator (SSG) is indicated as SSG’s open circuit.
5 - 4
5-4 RECEIVER ADJUSTMENTS
Receiver adjustments must be performed after software adjustment (0) and (1). SUB band must be OFF when adjusting MAIN band,
or main AF volume (max.counter clockwise) and SQL volume (max. clockwise) must be set when adjusting SUB band.
144 M
RECEIVER
PEAK/GAIN
144 M PEAK
(MAIN BAND)
144 M
TOTAL GAIN
(MAIN BAND)
144 M PEAK
(SUB BAND)
144 M
TOTAL GAIN
(SUB BAND)
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITION
MEASUREMENT
VALUE
POINT
UNIT LOCATION UNIT ADJUST
1
2
1
2
1
2
1
2
1
2
• Display frequency: Any
• Disconnect P501 (PA unit) from J51
on the MAIN unit.
• Connect a standard signal generator
to [VHF ANT] connector and set as:
Frequency : 146.0000 MHz
Level
: 7.1 mV* (–30 dBm)
Modulation : OFF
• Receiving
• Receiving
• Display frequency: 145.9800 MHz
• Mode
: FM
• Connect an SSG to [VHF ANT] con-
nector and set as:
Frequency : 145.9800 MHz
Level
: 3.2 µV* (–97 dBm)
Modulation : 1 kHz/±5.0 kHz Dev.
• Receiving
• Mode : USB
• Set an SSG as :
Frequency : 145.9815 MHz
Level
: 0.1 µV* (–127 dBm)
Modulation : OFF
• Receiving
• Display frequency: 145.9800 MHz
• Mode
: USB
• Set an SSG as :
Frequency : 145.9815 MHz
Level
: 1 mV* (–47 dBm)
Modulation : OFF
• Receiving
• Set an SSG as :
Level : OFF
• Receiving
• Sub display freq. : 145.9800 MHz
• Mode
: FM
• Connect an SSG to [VHF ANT] con-
nector and set as:
Frequency : 145.9800 MHz
Level
: 3.2 µV* (–97 dBm)
Modulation : 1 kHz/±5.0 kHz Dev.
• Receiving
• Mode : USB
• Set an SSG as :
Frequency : 145.9815 MHz
Level
: 0.1 µV* (–127 dBm)
Modulation : OFF
• Receiving
• Display frequency: 145.9800 MHz
• Mode
: USB
• Set an SSG as :
Frequency : 145.9815 MHz
Level
: 1 mV* (–47 dBm)
Modulation : OFF
• Receiving
• Set an SSG as :
Level : OFF
• Receiving
PA
Rear
panel
Rear
panel
Rear
panel
Rear
panel
Connect an RF volt-
meter to check point
P501 via the JIG
cable (A).
Connect an distortion
meter to [EXT SP]
connector with an
8
Ω
load.
Connect an AC milli-
volt meter to [EXT
SP] connector with
an 8
Ω
load.
Connect an AC milli-
volt meter to [EXT
SP] connector with
an 8
Ω
load.
Connect an distortion
meter to [EXT SP]
connector with an
8
Ω
load.
Connect an AC milli-
volt meter to [EXT
SP] connector with
an 8
Ω
load.
Connect an AC milli-
volt meter to [EXT
SP] connector with
an 8
Ω
load.
Maximum level
–14 dBm
Minimum audio distor-
tion level
Maximum noise output
level
1.0 V (0 dB)
100 mV (20 dB of AF
level difference as step
1.)
Minimum audio distor-
tion level
Maximum noise output
level
1.0 V (0 dB)
100 mV (20 dB of AF
level difference as step
1.)
PA
MAIN
Front
panel
MAIN
MAIN
Front
panel
MAIN
L521
R547
Adjust in
sequence
L51, L52
s e v e r a l
times.
L53, L352,
L353, L354
main [AF]
volume
R360
Adjust in
sequence
L651, L652
s e v e r a l
times.
L653, L851,
L852, L853
sub [AF]
volume
R857
After adjustment, connect P501 (PA unit) to J51 on the MAIN unit.