Icom IC-78 Service Manualvice Man

5 - 4
5-3 TRANSMITTER ADJUSTMENTS
IDLING
CURRENT
(for driver)
(for final
amplifier)
SWR
DETECTOR
TRANSMITTER
TOTAL GAIN
OUTPUT
POWER
Ic APC
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITION
MEASUREMENT
VALUE
POINT
UNIT LOCATION UNIT ADJUST
1
2
1
2
1
2
1
1
• Display frequency: 12.23000 MHz
• Mode : USB
• RF power : Minimum (L)
• Mic gain : Minimum (0)
• Disconnect J3601 (MAIN unit) and
preset R21, R24 (PA unit) to max.
counter clockwise.
• Transmitting
• Transmitting
• Display frequency: 12.23000 MHz
• Mode : USB
• RF power : Maximum (H)
• Connect J4 (FILTER) unit to GND.
• Connect an audio generator to
[MIC] connector and set as:
Frequency : 1.5 kHz
Level : 30 mVrms
• Transmitting
• Transmitting
• Display frequency: 12.23000 MHz
• Mode : USB
• RF power : Maximum (H)
• Mic gain : Center (50)
•
R2701 (MAIN unit) : Center
• Connect an audio generator to
[MIC] connector and set as:
Frequency : 1.5 kHz
Level : 3 mVrms
• Transmitting
• Transmitting
• Display frequency: 12.23000 MHz
• Mode : USB
• RF power : Maximum (H)
• MIC gain : Center (50)
• Connect an audio generator to
[MIC] connector and set as:
Frequency : 1.5 kHz
Level : 30 mVrms
• Transmitting
• Display frequency: 3.55000 MHz
• Mode : USB
• Connect CP4002 (MAIN unit) to
GND.
• RF power : Maximum (H)
• Mic gain : Center (50)
• Connect an audio generator to
[MIC] connector and set as:
Frequency : 1.5 kHz
Level : 30 mVrms
• Transmitting
PA
Rear
panel
FILTER
Rear
panel
Rear
panel
Rear
panel
Connect an ammeter
(3 A) between power
supply and the IC-78.
Connect an RF
power meter to [ANT]
connector.
Connect a digital
multimeter or oscillo-
scope to J5.
Connect an RF
power meter to [ANT]
connector.
Connect an RF
power meter to [ANT]
connector.
Connect an ammeter
(30A) between power
supply and the IC-78.
At the point where the
Tx current Increases
200 mA.
At the point where the
Tx current Increases
400 mA.
100 W
Minimum voltage
Maximum output
power
50 W
100 W
22 A
PA
Front
panel
FILTER
MAIN
MAIN
MAIN
R21
R24
Mic gain
control in
the quick
set mode
C17
L106,
L151,
L301,
L302,
L303,
L501
R503
R1707
R1720
After adjustment, connect J3601 on the MAIN unit.
After adjustment, disconnect J4 on the FILTER unit from GND.
After adjustment, disconnect CP4002 on the MAIN unit from GND.

Icom IC-78 Specifications

General

Brand	Icom
Model	IC-78
Category	Transceiver
Language	English