Icom IC-7700

4 - 7
4-4 ADJUSTMENTS ON THE PA200W BOARD
ADJUSTMENT ADJUSTMENT CONDITION OPERATION
ADJUSTMENT
POINT
VALUE
IDLING
(Preparation)
"IDLING" must be adjusted by cold-started.
1 • Mode : USB
• MIC gain : Minimum
• Connect an Audio Generator to the
MIC jack (see the page 4-2) and set
it as;
Frequency : 1.5 kHz
Level : 1 mV
––
2 1) Set 3 variable resisters to the preset
point.
2) Disconnect the W1 from the PA200W
BOARD, and connect an Ammeter
between the PA200W BOARD and
W1.
3) Measure the driving current, and
note it as the initial value.
R301, R407,
R410
Max.
counter
clockwise
IDLING
(DRIVER AMP.)
1 • Frequency : 14.100 MHz
• Mode : USB
• Transmitting
• Adjust the driving current with R301.
R301
+1.0 A
more than
initial value
IDLING
(FINAL AMP.)
1 • Frequency : 14.100 MHz
• Mode : USB
• Transmitting
• Adjust the driving current with
variable resisters.
R407 (for main
adjustment)
R425 (for critical
adjustment)
+2.0 A
more than
initial value
2 R410 (for main
adjustment)
R426 (for critical
adjustment)
+3.0 A
more than
initial value
3 Apply slight vibration to the PA200W BOARD, and verify that the current is stable against the vibration.