Icom IC-751A Service Manual page 55

6-2 PLL ADJUSTMENT
(1) AC POWER SUPPLY
© Output voltage
® Current capacity
(2) OSCILLOSCOPE
© Frequency range
© Measuring range
(3) FREQUENCY COUNTER
® Frequency range :
© Frequency accuracy
® Sensitivity
(4) RF VOLTMETER
: 13.8V DC
: 20A or more
: DC ~ 20MHz
: 0.01 ~ 10V
0.1 ~ 90MHz
: +1ppm or better
: 100mV or better
® Frequency range
® Measuring range
: 0.1 ~ 80MHz
0.01 ~ 10V
RF | AC POWER
VOLTMETER SUPPLY
OSCILLO- m FREQUENCY
SCOPE ANT COUNTER
| Jt, D8,
}— R46, R202
L13, R1
J5 PLL UNIT
CJ
IC-751A
CALIBRATOR] 1 | ® Frequency display: 8.000OMHz PLL Connect an oscilloscope 3V TOP _ |CALIBRATOR
¢ LSB General mode to J1 pin 5. PANEL _ | CONTROL
REFERENCE |1 | @ Frequency display: 8.0Q00OOMHz PLL Connect a frequency 30.7200MHz PLL L2
FREQUENCY @ LSB General mode counter to R1 (R2 side).
PLL LO 1| © Frequency display: 8.0000MHz PLL Connect an RF Voltmeter) Adjust PLL L8
OUTPUT @ LSB Genera! mode to L13. to maximum
LEVEL output:
400mV ~
1Vp-p
LOCK 1 | © Frequency display: 8.0000MHz PLL Connect an oscilloscope 3V PLL L201
VOLTAGE LSB General mode to R202.
2 | © Frequency display: 7.9999MHz 1.5~2V Verify
HPL LOCK 1 | © Frequency display: 7.9999MHz PLL Connect an oscilloscope 6.5V PLL C78
VOLTAGE © LSB General mode to R46.
2 | © Frequency display: 14.9999MHz C88
® LSB General mode
3 | © Frequency display: 21.9999MHz C97
4 | © Frequency display: 29.9999MHz C107
5 | © Frequency display: 8.0Q00OMHz 3V L201
6 | @ Frequency display: 15.0000MHz
7 | © Frequency display: 22.0000MHz
8 | © Frequency display: 7.9999MHz Connect an oscilloscope 2.5V R43
¢ LSB General mode to the cathode of D8.
2nd Lo 1 | © Frequency display: 8.0000MHz PLL Terminate J5 to ground | Adjust to PLL L3~L5
OUTPUT ¢ LSB General mode with a 50 resistor. maximum
LEVEL Connect an RF Voltmeter) output:
to J5. 250~400mV
rms