Icom IC-7800 Service Manual Addendum page 375

4-2 OSC UNIT ADJUSTMENTS
ADJUSTMENT ADJUSTMENT CONDITION
1 • Set the OSC unit to the external ref-
REFERENCE
OUTPUT erence mode on the set mode.
• MAIN display frequency
• Connect an SSG to J71 on the
OSC unit and set as;
Frequency
Level
Modulation
• Terminates J73 with 50 Ω.
• Receiving
2 • Receiving
REF IN
OUTPUT
• Terminates J72 with 50 Ω.
• Receiving
REF OUT 3 • Set the OSC unit to the internal ref-
OUTPUT erence mode on the set mode.
• Receiving
• Terminates J73 with 50 Ω.
• Receiving
• Terminates J72 with 50 Ω.
• Receiving
*This output level of a standard signal generator (SSG) is indicated as SSG's open circuit.
MEASUREMENT
UNIT
OSC
: 10.000 MHz
: 10.000 MHz
: 71 mV* (–10 dBm)
: OFF
OSC
OSC
4 - 2
LOCATION
Connect an RF volt- Maximum voltage
meter to J72.
Connect an RF volt- 0 dBm ±3.0 dB
meter to J72.
Connect an RF volt- 0 dBm ±3.0 dB
meter to J73.
Connect an RF volt- –10.0 dBm ±3.0 dB
meter to J71.
Connect an RF volt- 0 dBm ±3.0 dB
meter to J72.
Connect an RF volt- 0 dBm ±3.0 dB
meter to J73.
ADJUSTMENT
POINT
VALUE
UNIT ADJUST
OSC Adjust
repeatedly
L61,
L62
Verify
Verify
Verify
Verify
Verify