Sony HCD-MD555 Service Manual page 11

CHECK BEFORE STARTING PARTS REPLACEMENT AND ADJUSTMENT
Cause of defect can be approximately located by performing the following checks before starting repair work. For the detailed procedure,
refer to "SECTION 6 ELECTRICAL ADJUSTMENTS".
Laser power check
(page 44)
Traverse check
(page 45)
Focus bias check
(page 46)
CPLAY check
(page 46)
Self-record/playback check
(REC/PLAY)
(page 46)
TEMP check
(temperature compensation
offset adjustment)
(page 44)
Note: The criterion of judgement is presented only for the purpose of judgment whether specifications are satisfied or not. This is not the
specification values of adjustments.
When any adjustments are attempted, use the specification values that are described in the respective adjustment procedures.
Criterion of judgement
(If the value does not satisfy the following
specification value, it is judged as defective.)
• 0.9 mW power
Specification value: 0.84 to 0.92 mW
• 7.0 mW power
Specification value: 6.8 to 7.2 mW
• Iop (when 7 mW)
The Iop value that is indicated on the
optical pickup unit ±10 mA
• Traverse waveform
Specification value: Offset 10 % or less
• Error rate check
Specification value: At all points of a, b, c
C1 error 220 or less
AD error 2 or less
• Error rate check
Specification value:
a. When the test disc (MDW-74/AU-1) is
used
C1 error 80 or less
AD error 2 or less
b. When the check disc (TDYS-1) is used
C1 error 50 or less
• Error rate check with CPLAY
Specification value:
C1 error 80 or less
AD error 2 or less
• NG when "T=@@(##)[NG" is displayed
(@@ and ## are arbitrary numbers.)
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Countermeasure when result of judgement
is defective
• Cleaning the optical pickup
• Re-adjustment
• Replacement of the optical pickup
• Replacement of the optical pickup
• Replacement of the optical pickup
• Replacement of the optical pickup
• Replacement of the optical pickup
When test result is all the time defective:
• Replacement of the over-write head
• Check that circuits in the peripheral of the
over-write head are not open
When test result is defective from time to
time:
• Check if the over-write head is not deformed
• Mechanical check on parts around the sledding
mechanism
• Check that circuits in the peripheral of D101
(BD board) are not open
• Check signals in the peripheral of IC101, 121,
CN102, 103 (BD board)