Adjustments On The Pa200W Board - Icom IC-7700 Service Manual

4-4 ADJUSTMENTS ON THE PA200W BOARD

ADJUSTMENT ADJUSTMENT CONDITION
IDLING "IDLING" must be adjusted by cold-started.
(Preparation)
1 • Mode
• MIC gain
2
IDLING 1 • Frequency
(DRIVER AMP.) • Mode
• Transmitting
IDLING 1 • Frequency
(FINAL AMP.) • Mode
• Transmitting
2
3 Apply slight vibration to the PA200W BOARD, and verify that the current is stable against the vibration.
: USB • Connect an Audio Generator to the
: Minimum MIC jack (see the page 4-2) and set
it as;
Frequency
Level
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.
: 14.100 MHz • Adjust the driving current with R301.
: USB
: 14.100 MHz • A d j u s t t h e d r i v i n g c u r r e n t w i t h
: USB variable resisters.
4 - 7
OPERATION
: 1.5 kHz
: 1 mV
ADJUSTMENT
VALUE
POINT
– –
Max.
R301, R407,
counter
R410
clockwise
+1.0 A
R301 more than
initial value
R407 (for main
+2.0 A
adjustment)
more than
R425 (for critical
initial value
adjustment)
R410 (for main
+3.0 A
adjustment)
more than
R426 (for critical
initial value
adjustment)