SCD-1, SCD-777ES - Sony Audio Service Manual (repair manual). Page 5

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In terms of the optical pickups, which read signals, a twin pickup system has been adopted for reading CDs (wavelength: 780nm) and

SACDs (wavelength: 650nm). Although these two optical blocks are unified, their circuit operations are independent, so that if there is
trouble with one, the other will still operate with no problem.

At the base of the optical block, there are two soldered short lands for preventing damage from static electricity. When replacing the

optical block, a flexible board must be connected to the connector and the soldering removed.

A stationary optical mechanism used in high-quality CD players and the like was adopted. The spindle motor, which chucks the disc,

moves horizontally as the disc is fed. This mechanism reduces servo current fluctuations and thus improves playback.

Disc chucking is a manual process in which the stabilizer is placed on top of the disc. As the stabilizer has been made specially for this

model, stabilizers from other CD players cannot be used.

When transporting the set or placing it in long-term storage, make sure to remove the stabilizer from inside it.
As the stabilizer is fairly heavy, if the unit is subjected to shock without releasing the chucking, it could damage the spindle motor’s
shaft. In addition, leaving the stabilizer on top of the spindle motor for a long time could negatively affect the rubber on the chucking
plate.
If a power supply problem prevents the loading panel from opening, remove the top board, rotate the loading motor by hand, and
remove the stabilizer. When removing the top board, do it so that the stabilizer is pulled straight out from the spindle motor’s shaft.
(See “Service Manual for Primary Service,” p. 13.)

Circuits have primarily been configured with the following five boards.

Mounted to this board is the RF amplifier, which amplifies signal output from the optical block. Signals amplified with the RF amplifier

are output to the main board.

Built into the main board are main microprocessor, RAM and nearly all other digital processing circuits. Signals output from the RF board

are subjected to digital signal processing and output to the audio board.

Subjects digital signals output from the main board to D/A conversion, amplifies them with the amp circuit and outputs them. In consid-

eration of sound quality, layout has been given left-right symmetry.

AC voltage input from the power cord is reduced by power transformers, one for digital circuits and one for analog circuits, and input to

the power board. The power board’s series regulator produces and outputs different voltages for analog and digital circuits.

Mounted to this board are the FL tube, FL driver, and display microprocessors. Displays depend on the main board’s microprocessor

output.

OP

RF board

AUDIO board

DISPLAY board

POWER board

MAIN board

Audio
signal