Sony MVC-CD300 Service Manual page 70

7-4. Write (CDR) Adjustment
7-4-1. Jump Adjust
Purpose:
• Adjust the amount of overrun after jump of the OP (optical device)
is minimum.
• Adjust the kick voltage in accordance with the convergence status
after jump.
Trouble Symptom
NG is displayed.
Cause of Trouble
Convergence after jump has not ended within the specified time.
Remedial Measure
Replace the OP. (The OP that is removed in this step can be
used in other machine without trouble by combining with the
other MD-083 board in most case. Therefore, store the removed
OP and re-use it.)
7-4-2. Adjust WFB
Note: WFB =Write Focus Bias
Purpose:
Check variation of the Write Focus fine adjustment depending upon
the individual OP (optical device).
Trouble Symptom
No symptom is displayed. (The OK message always appears because
OK/NG judgment is not performed.)
7-4-3. 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-R disc can cause this error.)
Remedial Measure
• When the CD-R disc has scars or dust, replace the CD-R
disc with the new one and perform readjustment.
• When the CD-R disc is free from scars or dust, replace the
OP (optical device).
7-4-4. Focus Bias ATIP
Purpose:
Perform self-recording and playback. Read the ATIP (Absolute time
in pre-groove) and perform fine adjustment of focus and
measurement.
Trouble Symptom
No symptom is displayed. (The OK message always appears because
OK/NG judgment is not performed.)
7-4-5. Read Asymmetry After ATER
Purpose:
The segment that is recorded in section "7-4-4. Focus Bias ATIP" 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.
• BLER (block error rate) has exceeded the specification value.
• The CD-R disc has scars or dust.
Remedial Measure
• When the CD-R disc has scars or dust, replace the CD-R
disc with the new one and perform readjustment starting from
section "7-4-4. Focus Bias ATIP".
• When the CD-R disc is free from scars or dust, perform
readjustment starting from "7-1. Laser Power Adjustment"
step.
7-4-6. Self RF Jitter Check
Purpose:
Check the variation of jitter caused by OP (optical device) when the
CD-R 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.
7-4-7. Seek Check
Purpose:
Check that the seek operation is not abnormally slow.
Trouble Symptom
NG is displayed.
Cause of Trouble
• Load to the sled mechanism is too large.
• Torque of the sled motor is low.
• A foreign substance sticks to the lead screw or the gear part,
so the movement of them is obstructed.
Remedial Measure
• Replace the OP lead stopper.
7-4-8. Shock Level Adjust Check
Purpose:
Modify the initial value for the detection of the shock detection
circuit of the signal system.
Trouble Symptom
NG is displayed.
Cause of Trouble
Comparator or latch circuit is defective so that the detection
information is not sent to the CPU.
Remedial Measure
• Check the circuit starting from IC013 (RF PROCESS IC)
FE output (pin qf) to CPU (IC404 pin of).
IC013 → IC010 → IC014 → IC423 → IC400 → IC404
• Check the circuit starting from IC013 (RF PROCESS IC)
TE output (pin qd) to CPU (IC404 pin of).
IC013 → IC200 → IC208 → IC423 → IC400 → IC404
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