Pll Adjustment - Icom IC-78 Service Manualvice Man

5-2 PLL ADJUSTMENTS
ADJUSTMENT ADJUSTMENT CONDITION
REFERENCE 1 • Display frequency: Any
FREQUENCY • Set C16 as illustration at below.
• Receiving
2
3
1 • Display frequency: 29.99999 MHz
VCO LOCK
VOLTAGE • Receiving
2 • Display frequency: 0.03000 MHz
• Receiving
1ST LO 1 • Display frequency: 29.99999 MHz
OUTPUT • Mode
• Receiving
LEVEL
2 • Display frequency: 0.03000 MHz
• Mode
• Receiving
2ND LO 1 • Display frequency: 14.10000 MHz
OUTPUT • Mode
LEVEL • Receiving
1 • Display frequency: 14.10000 MHz
BFO
OUTPUT • Mode
• Receiving
2
3 • Mode
• Receiving
• PLL unit (bottom view)
CP1
MEASUREMENT
UNIT
PLL
PLL
PLL
: USB
: LSB
PLL
: USB
PLL
: USB
: AM
5 - 2
LOCATION
Turn L6, L7 on the PLL unit to downside for
Connect a frequency
presetting until the frequency counter reads
counter to check
frequency.
point P1.
64.00000 MHz
Connect an RF volt-
Maximum level
meter to check point
P1.
Connect a digital
multimeter or oscillo-
scope to check point
CP1.
More than 0.8 V
Connect an RF volt-
–3 dBm to +3dBm
meter to check point
P4.
Connect an RF volt-
–2 dBm to +4 dBm
meter to check point
P1.
Connect an RF volt-
–18 dBm to –12 dBm
meter to check point
P5.
Connect a frequency
counter to check
point P5.
C16
ADJUSTMENT
POINT
VALUE
UNIT ADJUST
PLL
4.15 V PLL
456.5 kHz
No output
C16
CP1
VCO lock voltage
check point
L4
L6, L7
C165
Verify
Verify
Verify
Verify