Transmitter Adjustments - Icom IC-718 Service Manual Addendum

5-3 TRANSMITTER ADJUSTMENTS

ADJUSTMENT ADJUSTMENT CONDITION
IDLING 1 • Display frequency: 14.10000 MHz
CURRENT • Mode
• RF power
(for driver)
• Mic gain
• Disconnect J3601 (MAIN unit) and
preset R21, R24 (PA unit) to max.
counter clockwise.
• Transmitting
(for final 2 • Transmitting
amplifier)
After adjustment, connect J3601 on the MAIN unit.
SWR 1 • Display frequency: 14.10000 MHz
• Mode
DETECTOR
• RF power
• Connect J4 (FILTER) unit to GND.
• Connect an audio generator to
[MIC] connector and set as:
Frequency
Level
• Transmitting
2 • Transmitting
After adjustment, disconnect J4 on the FILTER unit from GND.
TRANSMITTER 1 • Display frequency: 14.10000 MHz
• Mode
TOTAL GAIN
• RF power
• Mic gain
• R2701 (MAIN unit): Center
• Connect an audio generator to
[MIC] connector and set as:
Frequency
Level
• Transmitting
2 • Transmitting
1 • Display frequency: 14.10000 MHz
OUTPUT
POWER • Mode
• RF power
• MIC gain
• Connect an audio generator to
[MIC] connector and set as:
Frequency
Level
• Transmitting
1 • Display frequency: 3.55000 MHz
Ic APC
• Mode
• Connect CP4002 (MAIN unit) to
GND.
• RF power
• Mic gain
• Connect an audio generator to
[MIC] connector and set as:
Frequency
Level
• Transmitting
After adjustment, disconnect CP4002 on the MAIN unit from GND.
MEASUREMENT
UNIT
PA
: USB
: Minimum (L)
: Minimum (0)
Rear
: USB panel
: Maximum (H)
: 1.5 kHz
: 30 mVrms
FILTER
Rear
: USB panel
: Maximum (H)
: Center (50)
: 1.5 kHz
: 3 mVrms
Rear
: USB panel
: Maximum (H)
: Center (50)
: 1.5 kHz
: 30 mVrms
Rear
: USB panel
: Maximum (H)
: Center (50)
: 1.5 kHz
: 30 mVrms
5 - 4
LOCATION
Connect an ammeter At the point where the
(3 A) between power Tx current Increases
supply and the IC- 200 mA.
718.
At the point where the
Tx current Increases
400 mA.
Connect an RF
power meter to [ANT]
connector.
Connect a digital Minimum voltage
multimeter or oscillo-
scope to J5.
Connect an RF Maximum output
power meter to [ANT]
connector.
Connect an RF
power meter to [ANT]
connector.
Connect an ammeter
(30A) between power
supply and the IC-
718.
ADJUSTMENT
POINT
VALUE
UNIT ADJUST
PA
100 W Front Mic gain
panel control in
the quick
set mode
FILTER
MAIN
power
50 W
100 W MAIN
22 A MAIN
R21
R24
C17
L106,
L151,
L301,
L302,
L303,
L501
R503
R1707
R1720