Receiver Adjustments - Icom IC-910H Service Manual

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.
ADJUSTMENT ADJUSTMENT CONDITION
144 M 1 • Display frequency: Any
• Disconnect P501 (PA unit) from J51
RECEIVER
PEAK/GAIN on the MAIN unit.
• Connect a standard signal generator
to [VHF ANT] connector and set as:
Frequency : 146.0000 MHz
Level
Modulation : OFF
• Receiving
2 • Receiving
After adjustment, connect P501 (PA unit) to J51 on the MAIN unit.
144 M PEAK 1 • Display frequency: 145.9800 MHz
• Mode
(MAIN BAND)
• Connect an SSG to [VHF ANT] con-
nector and set as:
Frequency : 145.9800 MHz
Level
Modulation : 1 kHz/±5.0 kHz Dev.
• Receiving
2 • Mode
• Set an SSG as
Frequency : 145.9815 MHz
Level
Modulation : OFF
• Receiving
144 M 1 • Display frequency: 145.9800 MHz
• Mode
TOTAL GAIN
(MAIN BAND) • Set an SSG as
Frequency : 145.9815 MHz
Level
Modulation : OFF
• Receiving
2 • Set an SSG as
Level
• Receiving
144 M PEAK 1 • Sub display freq. : 145.9800 MHz
(SUB BAND) • Mode
• Connect an SSG to [VHF ANT] con-
nector and set as:
Frequency : 145.9800 MHz
Level
Modulation : 1 kHz/±5.0 kHz Dev.
• Receiving
2 • Mode
• Set an SSG as
Frequency : 145.9815 MHz
Level
Modulation : OFF
• Receiving
144 M 1 • Display frequency: 145.9800 MHz
TOTAL GAIN • Mode
• Set an SSG as
(SUB BAND)
Frequency : 145.9815 MHz
Level
Modulation : OFF
• Receiving
2 • Set an SSG as
Level
• Receiving
*This output level of a standard signal generator (SSG) is indicated as SSG's open circuit.
UNIT
PA
: 7.1 mV* (–30 dBm)
Rear
: FM panel
: 3.2 µV* (–97 dBm)
: USB
:
: 0.1 µV* (–127 dBm)
Rear
: USB panel
:
: 1 mV* (–47 dBm)
:
: OFF
Rear
: FM panel
: 3.2 µV* (–97 dBm)
: USB
:
: 0.1 µV* (–127 dBm)
Rear
: USB panel
:
: 1 mV* (–47 dBm)
:
: OFF
MEASUREMENT
LOCATION
Connect an RF volt-
meter to check point
P501 via the JIG
cable (A).
Connect an distortion Minimum audio distor-
meter to [EXT SP] tion level
connector with an
8 Ω load.
Connect an AC milli- Maximum noise output
volt meter to [EXT level
SP] connector with
an 8 Ω load.
Connect an AC milli-
volt meter to [EXT
SP] connector with
an 8 Ω load.
100 mV (20 dB of AF
level difference as step
1.)
Connect an distortion Minimum audio distor-
meter to [EXT SP] tion level
connector with an
8 Ω load.
Connect an AC milli- Maximum noise output
volt meter to [EXT level
SP] connector with
an 8 Ω load.
Connect an AC milli-
volt meter to [EXT
SP] connector with
an 8 Ω load.
100 mV (20 dB of AF
level difference as step
1.)
5 - 4
ADJUSTMENT
POINT
VALUE
UNIT
Maximum level PA
–14 dBm
MAIN
1.0 V (0 dB) Front
panel
MAIN
MAIN
1.0 V (0 dB) Front
panel
MAIN
ADJUST
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