Glass Disc for Mechanical Measurements And Settings

MECHANICAL MEASUREMENTS AND SETTINGS

Turntable height setting (see service manual CD player)

Place the small mirror 4822 395 90205 on the objective and the glass plate 4822 395 90204 (with pressure bar 4822 532 60906) on the turntable.

Place the device under a light source with a straight line underneath it (e.g. fluorescent tube with grid).
Set the tonearm to the center position. Rotate the device so that the tonearm is parallel to the line under the light source (see also Fig.).
Observe the reflection of the line on the glass plate and mirror in the direction and along its extension.
These lines must not be more than 4 mm apart. Position the device so that a line runs across the center of the mirror.

When the other line remains within the surface of the mirror, the distance is <4 mm.

Rotate the CD mechanism 90° relative to the previous position. The arm must remain in the center position (see Fig.).

Repeat the previous measurement.

Adjusting the angle setting

When adjusting the plate-light path angle at the factory, a compromise was sought between minimal angular deviation and minimal arm friction.

If the measurement shows that the angle falls outside the given tolerance, the angle must NOT be adjusted to minimize deviation, but rather within the tolerance. The new setting must lie between the old setting and the optimal setting.

After adjustment, the friction of the arm must be checked. This is done using a pressure gauge applied to the counterweight. The friction of the arm, measured over the entire range of motion, must not exceed 30 mN.

If the friction proves to be too high, the setting must be returned to the original value. Then replace the arm with a new one and check the angle again.
The angle is adjusted as follows:

Place the device on the service supports 4822 395 30202.
30 709 A15
Loosen screws C (See Fig.) until bearing plate D
can be moved.

Correct the angle setting by moving the bearing plate in the direction indicated in the figure.

Tighten screws C, ensuring that the setting
does not drift.

After this, check the angle setting again in two directions.