DHC-MD777, HMC-MD777 - Sony Audio Service Manual (repair manual). Page 10

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Before performing repairs, perform the following checks to determine the faulty locations up to a certain extent.
Details of the procedures are described in “5 Electrical Adjustments”.

• 0.9 mW power

Specified value : 0.84 to 0.92 mW

• 7.0 mW power

Specified value : 6.8 to 7.2 mW

lop (at 7mW)

• Labeled on the optical pickup

Iop value ± 10mA

• Traverse waveform

Specified value : Below 10% offset

• Error rate check

Specified value : For points a, b, and c
C1 error : Below 220
AD error : Below 2

• Error rate check

Specified value:
a.

When using test disc (MDW-74/AU-1)
C1 error : Below 80
AD error : Below 2

b.

When using check disc (TDYS-1)
C1 error : Below 50

• CPLAY error rate check

Specified value:
C1 error : Below 80
AD error : Below 2

• If NG, displayed as “T=@@ (##) [NG]”

(@@, ## are both arbitrary numbers)

Laser power check
(See page 33)

Traverse check
(See page 33)

Focus bias check
(See page 34)

C PLAY check
(See page 34)

Self-recording/playback
check
(REC/PLAY)
(See page 34)

Temperature
compensation
offset check
(See page 35)

Criteria for Determination
(Unsatisfactory if specified value is not satisfied)

• Clean the optical pick-up
• Adjust again
• Replace the optical pick-up

• Replace the optical pick-up

• Replace the optical pick-up

• Replace the optical pick-up

• Replace the optical pick-up

If always unsatisfactory:
• Replace the overwrite head
• Check for disconnection of the circuits around the

overwrite head

If occasionally unsatisfactory:
• Check if the overwrite head is distorted
• Check the mechanism around the sled

• Check for disconnection of the circuits around

D101 (BD (MD) board)

• Check the signals around IC101, IC121, CN102,

CN103 (BD (MD) board)

Measure if unsatisfactory:

The criteria for determination above is intended merely to determine if satisfactory or not, and does not serve as the specified value for adjustments.
When performing adjustments, use the specified values for adjustments.