Pll Adjustments - Icom IC-756PRO Service Manual

4-2 PLL ADJUSTMENTS

ADJUSTMENT ADJUSTMENT CONDITION
1 • Display frequency: Any
REFERENCE
FREQUENCY • Turn L52 on the PLL unit to 4 rota-
tion downside for presetting.
• Receiving
2
1 • Display frequency: 0.030000 MHz
LPL-A LOCK
VOLTAGE • Mode
• Receiving
1 • Display frequency: 14.999999 MHz
VCO-A LOCK
VOLTAGE • Mode
• Receiving
2 • Display frequency: 19.999999 MHz
• Mode
• Receiving
3 • Display frequency: 44.999999 MHz
• Mode
• Receiving
4 • Display frequency: 60.000000 MHz
• Mode
• Receiving
1 • Display frequency:
1LO-A
OUTPUT 0.030000 MHz, 7.999999 MHz
LEVEL 8.000000 MHz, 19.999999 MHz
20.000000 MHz, 44.999999 MHz
45.000000 MHz, 60.000000 MHz
• Receiving
LPL-B LOCK 1 • Sub display freq. : 0.030000 MHz
VOLTAGE • Mode
• Receiving
VCO-B LOCK 1 • Sub display freq. : 7.999999 MHz
VOLTAGE • Mode
• Receiving
2 • Sub display freq. : 19.999999 MHz
• Mode
• Receiving
3 • Display frequency: 44.999999 MHz
• Mode
• Receiving
4 • Display frequency: 60.000000 MHz
• Mode
• Receiving
1LO-B 1 • Sub display freq. :
OUTPUT 0.030000 MHz, 7.999999 MHz
8.000000 MHz, 19.999999 MHz
LEVEL
20.000000 MHz, 44.999999 MHz
45.000000 MHz, 60.000000 MHz
• Receiving
3LO 1 • Display frequency: Any
• Receiving
OUTPUT
LEVEL
S3LO 1 • Display frequency: Any
OUTPUT • Receiving
LEVEL
MEASUREMENT
UNIT
PLL
PLL
: USB
PLL
: USB
: USB
: USB
: USB
PLL
PLL
: USB
PLL
: USB
: USB
: USB
: USB
PLL
PLL
PLL
4 - 2
LOCATION
Connect a frequency 64.000000 MHz
counter to check
point P81.
Connect an RF volt- Maximum level
meter to check point (0 dB or more)
P81.
Connect a digital
multimeter or oscillo-
scope to check point
LPA.
Connect a digital
multimeter or oscillo-
scope to check point
LVA.
Connect an RF volt- 0 dBm or more
meter to check point
P351.
Connect a digital
multimeter or oscillo-
scope to check point
LPB.
Connect a digital
multimeter or oscillo-
scope to check point
LVB.
Connect an RF volt- 0 dBm or more
meter to check point
P651.
Connect an RF volt- –16 dBm or more
meter to check point
P701.
Connect an RF volt- –7 dBm or more
meter to check point
P801.
ADJUSTMENT
POINT
VALUE
UNIT ADJUST
PLL
adjustment)
2.0 V PLL
4.3 V PLL
4.3 V
4.3 V
4.3 V
2.0 V PLL
4.3 V PLL
4.3 V
4.3 V
4.3 V
L52
(R33
for critical
L81, L82
C154
C278
C258
C228
C208
Verify
C454
C578
C558
C528
C508
Verify
Verify
Verify