Pll Adjustment - Icom IC-M710RT Service Manual

4-3 PLL ADJUSTMENTS
ADJUSTMENT ADJUSTMENT CONDITION
REFERENCE 1 • Display frequency : 7.9999 MHz
LOOP LOCK • Mode
• Receiving
VOLTAGE
2 • Display frequency : 0.0300 MHz
MAIN 1 • Display frequency : 0.5000 MHz
LOOP LOCK • Receiving
VOLTAGE
2 • Display frequency : 29.9999 MHz
1 • Wait for 5 minutes after power ON.
REFERENCE
FREQUENCY • Terminate P2 on the PLL unit to
ground with a 50 Ω resister.
• Receiving
2
• MAIN AND PLL UNITS
C49
Reference loop
lock voltage
adjustment
J4
Reference loop
lock voltage
check point
J5
Main loop
lock voltage
check point
L24
Main loop
lock voltage
adjustment
MEASUREMENT
UNIT
PLL Connect
: J3E multimeter or oscillo-
scope to check point
J4.
PLL Connect
multimeter or oscillo-
scope to check point
J5.
PLL Connect an RF volt-
meter to check point
P2.
Connect a frequency
counter
point P2.
4 - 3
VALUE
LOCATION
a digital 3.2 V
More than 1.5 V
a digital 4.0 V
More than 1.0 V
Maximum level
(More than +2 dBm)
60.000000 MHz
to check
ADJUSTMENT
POINT
UNIT ADJUST
PLL C49
Verify
PLL L24
Verify
PLL L4, L5
L3
P2 Reference
frequency
check point
L4
Reference
frequency
L3
adjustment
L5