Sony MVC-CD300 Service Manual page 71

7-5. Write (CDRW) Adjustment
7-5-1. RW FE
Purpose:
Perform this adjustment to minimize the variations in focus error
amplitude and the offset caused by the OP (optical device).
Trouble Symptom
NG is displayed.
Cause of Trouble
As the result of adjustment, variation has exceeded the
specification value.
Remedial Measure
Replace the OP (optical device).
7-5-2. Focus Gain, Tracking Gain
Purpose:
Perform this adjustment to minimize the variations in the focus gain
and the tracking gain caused by the OP (optical device).
Trouble Symptom
NG is displayed.
Cause of Trouble
As the result of adjustment, variation has exceeded the
specification value.
Remedial Measure
Replace the OP (optical device).
7-5-3. Erase Focus Gain
Purpose:
Perform this adjustment to minimize the variations in the erase focus
gain caused by the OP (optical device).
Trouble Symptom
NG is displayed.
Cause of Trouble
As the result of adjustment, variation has exceeded the
specification value.
Remedial Measure
Replace the OP (optical device).
7-5-4. ATER Check
Note: ATER =Absolute time in pre-groove error rate
Purpose:
Measures the number of the ATIP (Absolute time in pre-groove)
errors that have occurs during recording.
Trouble Symptom
NG is displayed.
Cause of Trouble
The number of the ATIP errors during recording have exceeded
the specification value.
(Scars and stain of the CD-RW disc can cause this error.)
Remedial Measure
• When the CD-RW disc has scars or dust, replace the CD-
RW disc with the new one and perform readjustment.
• When the CD-RW disc is free from scars or dust, replace the
OP (optical device).
7-5-5. Read Asymmetry After ATER
Purpose:
The segment that is recorded in section "7-5-4. ATER Check" is
played back so that the non-uniformity of the signal symmetry of
the 3T and 11T signals are measured.
Trouble Symptom
NG is displayed.
Cause of Trouble
• Asymmetry has exceeded the specification value.
• After ATIP error rate has exceeded the specification value.
• The CD-RW disc has scars or dust.
Remedial Measure
• When the CD-RW disc has scars or dust, replace the CD-
RW disc with the new one and perform readjustment starting
from section "7-5-4. ATER Check".
7-5-6. BLER Check
Note: BLER =Block error rate
Purpose:
The segment that is recorded in section "7-5-5. Read Asymmetry
After ATER" is played back so that the BLER are measured.
Trouble Symptom
NG is displayed.
Cause of Trouble
The BLER has exceeded the specification value.
Remedial Measure
• When the CD-RW has scars or dust, replace the CD-RW
with the new one and perform readjustment starting from
"7-5-5. Read Asymmetry After ATER".
• When the CD-RW is free from scars or dust, perform
readjustment starting from "7-1. Laser Power Adjustment"
step.
7-5-7. Self RF Jitter Check
Purpose:
Check the variation of jitter caused by OP (optical device) when the
CD-RW is self-recorded/-played back.
Trouble Symptom
The measured value of the jitter has exceeded the allowable range
of specifications. (Jitter is 8 ns or less.)
Cause of Trouble
The SKEW adjustment is incomplete and needs readjustment.
Remedial Measure
Repeat the SKEW adjustment and the subsequent adjustments.
If the trouble is not remedied even the SKEW adjustment is
performed, replace the OP.
7-5-8. Write Drive ID
Purpose:
Writing down the ID when the MD adjustment is completed.
("FFFF" is written in the address 50 and "0000 " is written in the
address 51 of the EEPROM.)
— 26 —