Icom IC-7400 Service Manual

5 - 4
5-3 TRANSMITTER ADJUSTMENTS
IDLING
CURRENT
(for driver)
(for HF/50 MHz
band final
amplifier)
(for 144 MHz
band final
amplifier)
144 M PEAK
TX PEAK
TRANSMITTER
TOTAL GAIN
Ic APC
1
2
3
6
1
1
2
3
1
1
• Displayed freq. : 14.100000 MHz
• Mode : USB
• [MIC GAIN] : Max.CCW
• [RF POWER] : Max. CW
• [TUNER] : OFF
•
Preset R11, R18, R109, R204, R215
(PA unit) to max. counter clockwise.
• Transmitting
• Transmitting
4 • Transmitting
5
• Transmitting
• Displayed freq. : 144.00000 MHz
• Mode : USB
• Transmitting
• Transmitting
• Displayed freq. :
146.00000 MHz
• Mode : RTTY
• Transmitting
• Displayed freq. : 145.00000 MHz
• Mode : USB
• Set following controls as:
[RF POWER] : Max. CW
[MIC GAIN] : Center
[KEY SPEED]: Center
[PITCH] : Center
• Disconnect P1 (PA unit) from J151
(RF unit).
• Connect an audio generator to
[MIC] connector and set as:
Frequency : 1.5 kHz
Level : 1 mVrms
• Transmitting
• Displayed freq. : 14.100000 MHz
• Mode : USB
• Connect an audio generator as:
Frequency : 1.5 kHz
Level : 1 mVrms
• Transmitting
• Transmitting
• Displayed freq. : 14.100000 MHz
• Mode : USB
• [MIC GAIN] : Center
• Connect an audio generator to
[MIC] connector and set as:
Frequency : 1.5 kHz
Level : 1 mVrms
• Transmitting
• Mode : RTTY
• Connect CP300 to GND.
• Transmitting on the maximum TX
current band.
PA
Rear
panel
RF
Rear
panel
Rear
panel
Rear
panel
Connect an ammeter
between the power
supply and the
transceiver.
Connect an RF
power meter to the
[ANT 144MHz] con-
nector.
Connect a digital
multimeter or oscillo-
scope to the check
point J151.
Connect an RF
power meter to the
[ANT1] connector.
Connect an RF
power meter to
[ANT1] connector.
Connect an ammeter
between power sup-
ply and the transceiver.
+1.5 A
more than initial value
+500 mA
more than step "2"
+500 mA
more than step "3"
+500 mA
more than step "4"
+500 mA
more than step "5"
Maximum output
power
Maximum output
Level
50 W
Max. output power
50 W
23 A
PA
PA
RF
Front
panel
MAIN
MAIN
MAIN
R11
–
R18
R109
R204
R215
C202
Adjust in
sequence
L253, L252,
L251, L272
several times.
[MIC GAIN]
control
L330
R331
R555
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITION
MEASUREMENT
VALUE
POINT
TSUJDATINUNOITACOLTINU
After adjustment, re-connect P1 (PA unit) to J151 (RF unit).
After adjustment, disconnect the ammeter between the power supply and the transceiver.
Measure the driving
current, and note it as
the "initial value."

Icom IC-7400 Specifications

General

Brand	Icom
Model	IC-7400
Category	Transceiver
Language	English