Sony SCD-1 / SCD-777ES Service Manual ▷ View online
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(3) Adjustments
1. CLV jitter check
CLV jitter is confirmed from the difference between MNT4 (RFCK) and MNT5 (WFCK), which are ARP (IC702) test terminals. As CLV
jitter will worsen when there is spindle motor deterioration or trouble, the spindle motor’s quality can be judged.
As CLV jitter will differ when the disc’s inner and outer part are played, confirm it when playing track no. 5 on the test disc.
Fig. 4-3. CLV Jitter
JITTER
RFCK
WFCK
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2. Optical block height adjustment
Here, the screw that determines the height of the optical block and the tangential skew adjustment screw are adjusted. As these two
adjustment screws correlate in operations, they should each be adjusted several times, first one and then the other, to the optimal values.
With the PI signal, which is the signal that passes the RFDC signal through the LPF, the amount of light reflected from the disc is in
prorortion. When the objective lens is raised in the focus search operation, the reflected light of the disc’s front surface and signal surface are
detected in the PI signal (see Fig. 4-4.).
detected in the PI signal (see Fig. 4-4.).
With the FOUT signal, which controls focus operations, the best servo characteristics are obtained at VC voltage level. In keeping, so that
the best servo characteristics are obtained at the position of the disc’s signal surface (the position of the greatest level with the PI signal),
adjust this so that the value for B comes as close to 0 as possible. However, if B becomes a negative value, the operation for judging the disc
type could malfunction. Thus, adjust the value so that it is even slightly on the positive side.
adjust this so that the value for B comes as close to 0 as possible. However, if B becomes a negative value, the operation for judging the disc
type could malfunction. Thus, adjust the value so that it is even slightly on the positive side.
Fig. 4-4. Optical Block Height Adjustment Waveform
Note: Setting the playback mode
When adjustment 1 mode has been set, SACD will be set for the type of disc to be played. Then, when CDs, DLs, HBs and other disc
types are detected using code 30 of adjustment 1 mode, the type of disc to be played will be switched, preventing optical block height
from being adjusted.
In this case, either turn off the power once and reset adjustment 1 mode and return to SACD mode or use code 30 again, have the SL
disc’s type detected, and then make the adjustment.
types are detected using code 30 of adjustment 1 mode, the type of disc to be played will be switched, preventing optical block height
from being adjusted.
In this case, either turn off the power once and reset adjustment 1 mode and return to SACD mode or use code 30 again, have the SL
disc’s type detected, and then make the adjustment.
Note: Tangential skew adjustment
The volume for tangential skew adjustment cannot be turned over 90 degrees in one direction. In keeping, it the jitter value does not
improve even when the volume is rotated slightly in one direction at the time of adjustment, make the adjustment in the reverse
direction.
improve even when the volume is rotated slightly in one direction at the time of adjustment, make the adjustment in the reverse
direction.
VC
PI
FOUT
VC
A
B
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3. Overall adjustment
With the overall adjustment, when the automatic adjustment of one disc type is completed, the adjustment data to the present will be
deleted and the new data recorded. In keeping, if an error occurs during automatic adjustment, the adjustment data for that disc type will not
have been rewritten. When “XX END” is displayed (with CD, SL or DL appearing instead of XX),the adjustment data for that disc type will
have been rewritten.
have been rewritten. When “XX END” is displayed (with CD, SL or DL appearing instead of XX),the adjustment data for that disc type will
have been rewritten.
When automatic adjustment of the three types of discs has been completed, the adjusted values will be displayed with code 61; confirm
that the specified values (between U and L) have been adjusted. If separated from the specified values, confirm the servo circuit.
4. What to do when adjustments cannot be made
If the items confirmed and adjusted do not meet the specified values, do the following.
Traverse confirmation and “S curve” confirmation: Replace the optical block.
RF level confirmation:
RF level confirmation:
If the level is low, clean the lens. If the level is still outside the standard, replace the
optical block.
If only the jitter is poor, adjust OP height. If it is still outside the standard, replace the
optical block.
optical block.
If only the jitter is poor, adjust OP height. If it is still outside the standard, replace the
optical block.
CLV jitter confirmation:
Replace the spindle motor.
Optical block height adjustment:
If it cannot be adjusted, replace the optical block.
In addition, after making the adjustment, confirm the RF level and jitter value. If they
are outside the standards, replace the optical block.
In addition, after making the adjustment, confirm the RF level and jitter value. If they
are outside the standards, replace the optical block.
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Sony Corporation
Home Audio Division Company
9-928-926-41
2000B0900-1
Printed in Japan © 2000. 2
Published by Quality Assurance Dept.
