Philips cdv 495 service manual

Page 1

FI'IILI -S CDV4S 5

CDM. SERVO AND MOTOR CIRCUIT DESCRIPTION FOR
CDV455

1 CDM

1.1 Mechanical pans

1.1.1 Dismantling the carriage
1.1.2 Mounting the carriage

1.2 The light path

1.3 Sigma PI board

1.3.1 The laser supply

1.3.2 HF amplifier

1.3.3 EFM amplifier

3.4 EFM level detector

.35 Focus error signal generation

.36 Radial error signal generation

.3] Tilt error signal generation with Tilt LED power
supply

1.4 Adjustments

1.4.1 a setting

1.4.2 Y setting

1.4.3 Grating setting

1.4.4 Laser current setting

1.4.5 Tilt error (TE) offset setting

1
1
1
1

2 SEaVICE SOFTWARE

2.1 Start-up procedure

2.2 Calling up the service mode

2.3 On Screen Display

2.4 Service info on the FT D

2.5 Start-up phases with a CD( 8 cm and 12 cm) or
CDV clip disc

2.6 Start-up phases With a CDV LP or CDV single

3 SERVO CIRCUIT

3.1 Servo-uP circuit

32 Focus circuit

3.3 Radial control circuit

3.4 TPI correction circuit

3.5 Tilt motor circuit

4 MOTOR CIRCUIT

4.1 DSCM2 circuit

4.2 Tray motor Circuit

5 EXPLODED VIEW COM

6 EXPLODED VIEW LOADING

7 DEMOUNTING OF THE LOADING
6 CIRCUIT DIAGRAMS

Page 2

1 COM

The CDM operates according to the principle 0'
three-beam tracking.

The parts at the CDM are mounted on the chassis
pos.506 together with the LOADING parts.

See exploded view or COM and exploaed vlew of
LOADING.

Definitions: (see fig, 1)

roex a
or ADJUST
I5

Fig, 1

- Movement of the objective perpendicular to the tracks

irom the centre of the turntable motor is the X direction.

- Movement oi the objective perpendicular to the X
direction is the Y direction.

- Rotation around the X axis is the o setting.

- Rotation around the Y axis is the 5 setting.

1.1 Mechanical parts

The most important parts are: (see fig. 2)

- ms 222 the carriage. on which the light path is
mounted.

- ms 214 to pos. 221 constitute the Carriage drive. for
movement in the X direction.

- pos. 224 to 905. 234 constitute the tilt control
mechanism for the 8 setting.

- pos. 223 is the mechanism for the a setting.

- pos. 208 is the turntable motor, a Hall motori

- Sigma pi board, with the circuits for the generation oi
the tracking signals, HF Signal and laser supply.

FI-IILIFS CDV4S 5

1.1.1 Dismantling the carriage

t
2
3
4
5
6

. Detach the llexprints from the connectors.

i Detach the spring pos. 202 from pos. 203.

i Loosen the two screws of the a setting mechanism
posi 223.

i Withdraw the carriage bracket from the tilt motor
suspension.

. The carriage can now be taken out of the CDM.

. Measure the distance D of the faulty carriage, shown
in fig. 19, for the Y setting ol the new carriageil See
1.42 V setting.