Rx Adjustments - Icom IC-7851 Servise Manual

3-7 RX ADJUSTMENTS

• RX adjustment screen
ADJUSTMENT
-Preparation- 1 • Connect an SSG to the [ANT1] connector.
-Preset- 2 1) Set the coils and pots to their preset position.
2) Push [F-5] (RX) to enter the RX adjustment menu.
MAIN 1st LO LEVEL 1 1) Push [F-3] (Gain A) several times until "Total Gain A HF
[ Total Gain A HF
PRE OFF 3k ref] 2) Connect a voltage meter to CP2201 (RF-A UNIT).
3) Rotate R2213 to adjust the voltage.
2 1) Set the SSG as:
2) Rotate C3805 and R3610 to adjust the output AF signal
3) Push [F-3] (Exit).
1 1) Push [F-4] (Gain B) several times until "Total Gain B HF
SUB
1st LO LEVEL
[ Total Gain B HF 2) Connect a voltage meter to CP2201 (RF-B UNIT).
PRE OFF 3k ref] 3) Rotate R2213 to adjust the voltage.
2 1) Set the SSG as:
2) Rotate C3805 and R3610 to adjust the output AF signal
3) Push [F-3] (Exit).
OPERATION
(Both on RF-A and RF-B UNITs)
• L3111 and L3112: 3 rotations from the top.
• L3121 and L3122: 3.5 rotations from the top.
• L3131 and L3132: 6 rotations from the top.
• R2510 and R2511: Center position.
PRE OFF 3k ref" appears.
• Frequency: 14.0765 MHz
• Level: +94 dBµ
level.
• Returns to the RX adjustment menu.
PRE OFF 3k ref" appears.
• Frequency: 14.0765 MHz
• Level: +94 dBµ
level.
• Returns to the RX adjustment menu.
3
rotations
Core
3.5
rotations
Core
6
rotations
Core
3-14
ADJUSTMENT
VALUE
ITEM
–
Their preset
position.
(Shown in the left
column.)
14.5 V (±0.1 V)
R2213
(RF-A UNIT)
Minimum
audio level.
C3805 and R3610
(RF-A UNIT)
14.5 V (±0.1 V)
R2213
(RF-B UNIT)
Minimum
audio level.
C3805 and R3610
(RF-B UNIT)
–