Transmitter Adjustments - Icom IC-718 Service Manual

Mar. 2010

5-3 TRANSMITTER ADJUSTMENTS

ADJUSTMENT
IDLING 1 • Display frequency : 14.10000 MHz
CURRENT • Mode : USB
(for pre-driver) • RF power : Minimum (L)
• Mic gain : Minimum (0)
• Disconnect J3601 (MAIN unit) and
preset R51, R56, R58, R64 (PA
unit) to counterclockwise.
• Transmitting
(for driver) 2 • Transmitting
3
(for fi nal amplifi er) 4 • Transmitting
After the "IDLING CURRENT" adjustment, recover the connection of J3601.
SWR 1 • Display frequency : 14.10000 MHz
DETECTOR • Mode : USB
• RF power : Maximum (H)
• Connect J4 (FILTER unit) to GND.
• Connect an audio generator to
[MIC] connector and set as;
Frequency
Level
• Transmitting
2 • Transmitting
After the "SWR DETECTOR" adjustment, recover the connection of J4.
TRANSMITTER 1 • Display frequency : 14.10000 MHz
TOTAL GAIN • Mode : USB
• RF power : Maximum (H)
• R2701 (MAIN unit) : Center
• Mic gain : Center (50)
• Connect an audio generator to
[MIC] connector and set as;
Frequency
Level
• Transmitting
2 • Transmitting
OUTPUT 1 • Display frequency : 14.10000 MHz
POWER • Mode : USB
• RF power : Maximum (H)
• Mic gain : Center (50)
• Connect an audio generator to
[MIC] connector and set as;
Frequency
Level
• Transmitting
Ic APC 1 • Display frequency : 3.55000 MHz
• Mode : USB
• RF power : Maximum (H)
• Mic gain : Center (50)
• Connect CP4002 (MAIN unit) to
GND.
• Connect an audio generator to
[MIC] connector and set as;
Frequency
Level
• Transmitting
After the "Ic APC" adjustment, recover the connection of CP4002.
(Replacement page)
ADJUSTMENT
CONDITION
UNIT
PA
Rear
panel
:1.5 kHz
:30 mVrms
FILTER C o n n e c t a d i g i t a l
Rear
panel
:1.5 kHz
:3 mVrms
Rear
panel
:1.5 kHz
:30 mVrms
Rear
panel
:1.5 kHz
:30 mVrms
MEASUREMENT
LOCATION
1) Connect a digital 1) Set the voltage to
multimeter to the 0.5 V.
CP1. 2) Measure the idling
2) C o n n e c t a n current, and note
a m m e t e r ( 1 0 A ) i t a s t h e " i n i t i a l
between the power value."
supply and IC-718.
more than the initial value
more than the step "2"
more than the step "3"
C o n n e c t a n R F
power meter to [ANT]
connector.
Minimum voltage
multimeter to J5.
C o n n e c t a n R F Maximum output
power meter to [ANT]
connector.
C o n n e c t a n R F
power meter to [ANT]
connector.
Connect an ammeter
(30 A) between power
supply and the IC-718.
5 - 4
ADJUSTMENT
POINT
VALUE
UNIT ADJUST
PA
+400 mA
+400 mA
+2.0 A
100 W Front Mic gain
panel control
in the
"quick set
mode."
FILTER
MAIN L106,
power L151,
L301,
L302,
L303,
L501
50W R503
100 W MAIN R1707
22 A MAIN R1720
R51
R56
R58
R64
C17