Pll Adjustments - Icom IC-756PRO III Service Manual

4-2 PLL ADJUSTMENTS

ADJUSTMENT ADJUSTMENT CONDITION
1 • Display freq.
REFERENCE
• Turn L52 on the PLL unit to 4 rota-
FREQUENCY
tion downside for presetting.
• Receiving
2
1 • Display freq.
LPL-A LOCK
• Mode
VOLTAGE
• Receiving
1 • Display freq.
VCO-A LOCK
• Mode
VOLTAGE
• Receiving
2 • Display freq.
• Mode
• Receiving
3 • Display freq.
• Mode
• Receiving
4 • Display freq.
• Mode
• Receiving
1 • Display freq.
1LO-A
0.030000 MHz, 7.999999 MHz
OUTPUT
8.000000 MHz, 19.999999 MHz
LEVEL
20.000000 MHz, 44.999999 MHz
45.000000 MHz, 60.000000 MHz
• Receiving
1 • Sub display freq. : 0.030000 MHz
LPL-B LOCK
• Mode
VOLTAGE
• Receiving
1 • Sub display freq. : 7.999999 MHz
VCO-B LOCK
• Mode
VOLTAGE
• Receiving
2 • Sub display freq. : 19.999999 MHz
• Mode
• Receiving
3 • Display freq.
• Mode
• Receiving
4 • Display freq.
• Mode
• Receiving
1 • Sub display freq. :
1LO-B
0.030000 MHz, 7.999999 MHz
OUTPUT
8.000000 MHz, 19.999999 MHz
LEVEL
20.000000 MHz, 44.999999 MHz
45.000000 MHz, 60.000000 MHz
• Receiving
1 • Display freq.
3LO
• Receiving
OUTPUT
LEVEL
1 • Display freq.
S3LO
• Receiving
OUTPUT
LEVEL
MEASUREMENT
UNIT
: Any PLL
: 0.030000 MHz PLL
: USB
: 7.999999 MHz PLL
: USB
: 19.999999 MHz
: USB
: 44.999999 MHz
: USB
: 60.000000 MHz
: USB
: PLL
PLL
: USB
PLL
: USB
: USB
: 44.999999 MHz
: USB
: 60.000000 MHz
: USB
PLL
: Any PLL
: Any PLL
4 - 2
LOCATION
Connect a frequency 64.000000 MHz
counter to the check
point P81.
Connect an RF volt- Maximum level
meter to the check (0 dB or more)
point P81.
Connect a digital
multimeter or oscil-
loscope to the check
point LPA.
Connect a digital
multimeter or oscil-
loscope to the check
point LVA.
Connect an RF volt- –2 dBm or more
meter to the check
point P351.
Connect a digital
multimeter or oscil-
loscope to the check
point LPB.
Connect a digital
multimeter or oscil-
loscope to the check
point LVB.
Connect an RF volt- –2 dBm or more
meter to the check
point P651.
Connect an RF volt- –16 dBm or more
meter to the check
point P701.
Connect an RF volt- –10 dBm or more
meter to the 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