Transmitter Adjustments - Icom IC-910H Service Manual

5-5 TRANSMITTER ADJUSTMENTS

ADJUSTMENT ADJUSTMENT CONDITION
• Preset R131, R135, R150, R650 (PA unit) to max. counter clockwise.
PA UNIT 1
• Preset R3, R138, R503 (PA unit) to center position.
PRESETTING
• Preset C154, C659 (PA unit) to center position as illustration at right.
1 • Display frequency:
IDLING
[EUR], [KOR]
CURRENT
[USA-1], [AUS] 146.0000 MHz
(for 144 M)
• Mode
• Transmitting
2 • Transmitting
3 • Transmitting
4 • Display frequency:
(for 430 M)
[EUR], [KOR]
[USA-1], [AUS] 450.0000 MHz
• Mode
• Transmitting
RF PEAK 1 • Display frequency: 440.0000 MHz
(for 430 M) • Connect an SSG to P1 on the PA
unit via the JIG cable (A) and set as:
Frequency : 10.850 MHz
Level
Modulation : OFF
• Transmitting
2 • Set an SSG as:
Level
• Transmitting
(for 144 M) 3 • Connect an SSG to P501 on the PA
unit via the JIG cable (A) and set as:
Frequency : 10.850 MHz
Level
Modulation : OFF
• Display frequency: 146.0000 MHz
4
• Set an SSG as:
Level
• Transmitting
• Display frequency: Any
IF PEAK 1
• Mode
• MIC gain
• Connect an audio generator to
[MIC] connector and set as:
Frequency
Level
• Transmitting
• Display frequency: Any
CARRIER 1
• Mode
SUPPRESSION
• Mic gain
• Apply no audio signals to [MIC]
connector.
• Transmitting
2 • Mode
• Transmitting
3
• Repeat step 1, step 2 several times.
UNIT
145.0000 MHz
: CW
435.0000 MHz
: CW
Rear
panel
: 18 mV* (–22 dBm)
: 0.79 µV* (–2 dBm)
: 18 mV* (–22 dBm)
: 0.79 µV* (–2 dBm)
MAIN
: USB
: Center
: 1.5 kHz
: 2 mVrms
MAIN
: USB
: Minimum
: LSB
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MEASUREMENT
LOCATION
PA Connect an ammeter
(3 A) between power
supply and the IC-
910H.
Connect an RF
power meter to [UHF
ANT] connector.
Connect an RF
power meter to [VHF
ANT] connector.
Connect an RF volt-
meter to check point
J51 via the JIG cable
(B).
Connect a spectrum
analyzer to check
point J51 via the JIG
cable (B).
5 - 8
ADJUSTMENT
VALUE
UNIT
At the point where the PA
TX current increases
0.5 A.
At the point where the
TX current increases
1.0 A as step 1.
At the point where the
TX current increases
0.5 A as step 2.
At the point where the
TX current increases
1.0 A.
Maximum output PA
power
Refer page 5-16 software adjustment 6.
Maximum output PA
power
Maximum level MAIN
Minimum carrier level MAIN
POINT
ADJUST
R131
R135
(R138)
R650
R150
L1, L2
C154
C659
L2, L3
R206,
R215