Codec Adjustment - Icom ID-800H Service Manual

5-2 CODEC BOARD ADJUSTMENT
ADJUSTMENT
ITEM
POWER SUPPLY • Connect 5.0 V DC power supply to pin 29 ( ) and pin 30 ( ) of J301.
CONNECTIONS • Connect 8.0 V DC power supply to pin 28 ( ) and pin 30 ( ) of J301.
ENTERING • Connect the pin 14 of J301 to GND to enter the adjustment mode.
ADJUSTMENT MODE
CODEC 1 • Connect the frequency counter to CP101 through a
capacitor (1000 pF).
FREQUENCY
MODEM 1 • Connect the frequency counter to CP216 through a
capacitor (1000 pF).
FREQUENCY
MODURATION 1 • Connect the pin 1 of J301 to GND to enter the
transmit mode.
OUTPUT LEVEL
• Connect the oscilloscope to pin 21 of J301.
2 • Disconnect the pin 1 of J301 from GND after the adjustment to exit the transmit mode.
EXITING • Disconnect the pin 14 of J301 from GND to exit the adjustment mode.
ADJUSTMENT MODE
• CODEC BOARD (BOTTOM VIEW)
CP216
Modem frequency
check point
CP101
CODEC frequency
check point
• CODEC BOARD (TOP VIEW)
R264
Modulation output level
adjustment point
ADJUSTMENT CONDITION
5 - 3
OPERATION
• Adjust C102 to set to 16.38400 MHz ±10 Hz.
• Adjust C207 to set to 2.457600 MHz ±3 Hz.
• Adjust R264 to set to 350 mVp-p ±10 mV.
J301, pin 1
Entering transmit mode
pin 30
pin 29
pin 28
J301, pin 21
Modulation output level
check point
J301, Pin 14
Entering adjustment mode
Power supply
5.0 V DC / 1 A
Power supply
8.0 V DC / 1 A
C207
Modem frequency
adjustment point
C102
CODEC frequency
adjustment point