Tx Adjustments - Icom IC-7851 Servise Manual

3-6 TX ADJUSTMENTS

• TX adjustment screen
ADJUSTMENT
-PREPARATION- 1 1) Connect an RF power meter to the [ANT1] connector.
2) Push [F-4] (TX) to enter the TX adjustment menu.
3) Push [F-1] (Power).
[ POWER HF PRE- 2 1) Set R983 (MAIN UNIT) to the center position.
SET] 2) Push [F-7].
[ POWER 50M 3 1) Set R985 (MAIN UNIT) to the center position.
PRESET] 2) Push [F-7].
4 • Push [F-7].
[TX PEAK SET] 5 1) Trim the coils and capacitor to adjust the TX output power.
2) Push [F-7].
[RESIDUAL AM] 6 • Connect an Audio Generator to the MIC input [MIC], and then
7 • Rotate C1102 to adjust the TX output power.
8 • Push [F-7].
[TX TOTAL GAIN] 9 • Connect an Audio Generator to the MIC input [MIC], and
10 • Rotate R1074 to adjust the TX output power.
11 • Push [F-7].
TX POWER SET 12 1) Connect an Audio Generator to the MIC input [MIC], and
(HF)
-PREPARATION-
2) Push [F-7].
OPERATION
• "POWER HF PRESET" is displayed.
• "POWER 50M PRESET" is displayed.
• "TX POWER SET" is displayed.
• "TX PEAK SET" is displayed.
• "Residual AM" is displayed.
set it as:
• Frequency: 1.0 kHz
• Level: 10 mVrms
• "TX Total Gain" is displayed.
then set it as:
• Frequency: 1.5 kHz
• Level: 10 mVrms
• "POWER HF 0W" is displayed.
then set it as:
• Frequency: 1.5 kHz
• Level: 10 mVrms
• "POWER HF 5W" is displayed.
[POWER HF/50M 0W]
3-10
ADJUSTMENT
VALUE
ITEM/POINT
Push [F-4].
–
R983
(MAIN UNIT)
Center position
R985
(MAIN UNIT)
Center position
Push [F-7].
[TX POWER SET]
L1071, C1102, L1112 Maximum TX
(MAIN UNIT) output power
(Repeatedly)
–
C1102 Maximum TX
(MAIN UNIT) output power
Push [F-7].
–
–
R1074
(MAIN UNIT)
Push [F-7].
–
–
–
100 W
–