Sony MVC-CD300 Service Manual page 67

7-1. Laser Power Adjustment
7-1-1. EEPROM Preset
Purpose:
Prior to starting the adjustment, confirm the communication between
a PC (personal computer) and the MD (mechanism deck: DDX-
G2100).
Also, the EEPROM is initialized as minimum as possible that is
required for the adjustment. (Note)
Note: This initialization of the EEPROM aims at the adjustment of
troubleshooting. In the ordinary adjustment work, perform the
minimum initialization for the time being. If the adjustment cannot
be performed by all means, execute [EEPROM Initialize] in the
bottom of the Adjustment Menu (Engineer) screen to initialize all
the data of the EEPROM.
Trouble Symptom
• The check disc operation does not start (the seek sound cannot be
heard) even a disc is inserted in the BU adjustment jig and the
main power is turned on.
• USB cannot be recognized. The message "SONY DSC DDX-
G2100 " does not appear in the [Device Select] window of the
Adjustment Menu (Engineer) screen.
Cause of Trouble
• Communication is disabled. The possibility of the trouble of
the machine itself is scarce. Most troubles are caused by the
human errors during repair work. For example, flexible board
is inserted while the main power of the BU adjustment jig is
still turned ON.
Remedial Measure
• Click [EEPROM Menu] button on the Adjustment Menu screen
to read the EEPROM data. If data of the address 7F is "F5FE"
(backup mode), the communication is normal. If it is any value
(for example "F 5FD") other than "F5FE", the communication
is defective. Then, turn off the main power of the BU adjustment
jig and remove the jumper. Restart the equipment and the
normal communication can be set.
7-1-2. Cover Switch Check
Purpose:
Operation check of the disc cover open/close detection circuit.
Trouble Symptom
The message "Confirming cover open SW.....NG" appears on the
[Cover Switch Sensor] screen.
Cause of Trouble
• IC422 on the MD-083 board is defective.
• Input (pin 2) of IC002 on the MD-083 board is short-circuited.
Remedial Measure
Check IC422 and IC002.
7-1-3. Read Power
Purpose:
Adjust the read power of OP.
Trouble Symptom (1)
The laser power meter measurement value never increases even
though the [+] button is pressed.
Cause of Trouble
The laser emission is always turned off due to defective laser
power cut-off circuit (IC002 on the MD-083 board).
Remedial Measure
Check IC002.
Trouble Symptom (2)
The laser power meter measurement value does not reach the
specified value even though the [+] button is pressed..
Cause of Trouble
The laser output does not increase due to defect or life of the
laser diode within the OP (optical device).
Remedial Measure
Replace the OP (optical device).
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