Icom AT-140 Service Manual

4 - 2
4-2 ANTENNA TUNER ADJUSTMENTS
PHASE
DETECTOR
CIRCUIT
IMPEDANCE
DETECTOR
CIRCUIT
FORWARD
DETECTOR
CIRCUIT
SWR
DETECTOR
CIRCUIT
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITION
MEASUREMENT
VALUE
POINT
UNIT LOCATION UNIT ADJUST
1
2
3
4
• S1 : PRESET
• S4-7 : OFF
• Short pins of J13.
• Disconnect P6 from J6.
• Ground J15 with a jumper wire.
• TRANSCEIVER
Display freq. : 1.6 MHz
Output power : 10 W
(carrer only)
Transmitting
• Same as above
• Same as above
• Same as above
Connect an oscillo-
scope to the check
point pin 2 of J8.
Connect an oscillo-
scope to check
point pin 3 of J8.
Connect an oscillo-
scope to check
point pin 1 of J8.
Connect an oscillo-
scope to check
point pin 4 of J8.
5 V (Tune R194 just
before droped.)
5 V (Tune C7 just
before drope.)
1.4 – 2.4 V
0 – 0.1 V
R56
C7
Verify
Verify
TUNER TUNER
NOTE: • After adjustment, remove the jumper wires from J15 and ground.
• After adjustment, Disconnect pins of J13.
• After adjustment, reconnect P6 to J6 and set S1 to [NORMAL] position.
PRESET
NORMAL
OFF
S1
S4
J8
1
7
C7
J13
J15
J6
R194
Impedance detector
adjustment
Phase detector
adjustment
1
6
LED's

Icom AT-140 Specifications

General

Compatibility	IC-M802
Product color	Gray
Frequency range	1.6 - 30 MHz
Brand compatibility	ICOM
Quantity	1