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5 - 2
5-2 PLL ADJUSTMENTS
REFERENCE
FREQUENCY
VCO LOCK
VOLTAGE
1ST LO
OUTPUT
LEVEL
2ND LO
OUTPUT
LEVEL
BFO
OUTPUT
ADJUSTMENT
ADJUSTMENT
ADJUSTMENT CONDITION
MEASUREMENT
VALUE
POINT
UNIT
LOCATION
UNIT
ADJUST
1
2
3
1
2
1
2
1
1
2
3
• Display frequency: Any
• Set C16 as illustration at below.
• Receiving
• Display frequency: 29.99999 MHz
• Receiving
• Display frequency: 0.03000 MHz
• Receiving
• Display frequency: 29.99999 MHz
• Mode
: USB
• Receiving
• Display frequency: 0.03000 MHz
• Mode
: LSB
• Receiving
• Display frequency: 14.10000 MHz
• Mode
: USB
• Receiving
• Display frequency: 14.10000 MHz
• Mode
: USB
• Receiving
• Mode
: AM
• Receiving
PLL
PLL
PLL
PLL
PLL
Connect a frequency
counter to check
point P1.
Connect an RF volt-
meter to check point
P1.
Connect a digital
multimeter or oscillo-
scope to check point
CP1.
Connect an RF volt-
meter to check point
P4.
Connect an RF volt-
meter to check point
P1.
Connect an RF volt-
meter to check point
P5.
Connect a frequency
counter to check
point P5.
64.00000 MHz
Maximum level
4.15 V
More than 0.8 V
–3 dBm to +3dBm
–2 dBm to +4 dBm
–18 dBm to –12 dBm
456.5 kHz
No output
PLL
PLL
L4
L6, L7
C165
Verify
Verify
Verify
Verify
Turn L6, L7 on the PLL unit to downside for
presetting until the frequency counter reads
frequency.
C16
CP1
C16
CP1
VCO lock voltage
check point
• PLL unit (bottom view)
Summary of Contents for IC-718
Page 29: ...SERVICE MANUAL ADDENDUM CONTENTS PARTS LIST 1 BOARD LAYOUTS 19 VOLTAGE DIAGRAM 25 Jun 2011 ...
Page 49: ...Jun 2011 20 C16 CP1 PLL UNIT BOTTOM VIEW FILTER UNIT BOTTOM VIEW PA UNIT BOTTOM VIEW ...
Page 81: ...SERVICE MANUAL ADDENDUM CONTENTS PARTS LIST 1 BOARD LAYOUTS 16 VOLTAGE DIAGRAM 18 Jul 2009 ...
Page 196: ...9 4 VARISTOR BOARD BOTTOM VIEW PLL UNIT BOTTOM VIEW PA UNIT ...
Page 200: ...9 8 BOTTOM VIEW FILTER UNIT ...
Page 206: ...1 1 32 Kamiminami Hirano ku Osaka 547 0003 Japan S 13701MZ C1 q 2000 Icom Inc ...