Philips CDF 100 Service Manual page 10

4.2.1 Demounting of FLEX FOILCDM-9
e@ Remove the "flex foil" from the connector(s) on the
PCB by lifting the upper part of the connector and
taking the flex foil out. ( see fig. MDA 01408 )
© After disconnecting of the "flex foil" short-circuit the by
means of a paperclip or constructive clip.
®@ Note
Aid
Since laser, monitor diode and photodiodes are very
sensitive to electrostatic discharges, careless handling
during servicing may reduce life expectancy
drastically. For this reason care should be taken that
during servicing the potentials of the aids and yourself
are equal to that of the screening of the set.
a
DESCRIPTIONS
The system parts of the servo and decoder are:
- COM-9 optical pick up
+ TDA8808 bipolar photodiode signal processor
- TDA8809__ bipolar radial error processor
- SAA7310 NMOS Single Chip decoder
-SAA7321 NMOS digital filter with bitstream
DAC
5.1.1 CDM-9 optical pick up
Mechanics
The pick-up is mounted at the end of a low-inertia
balanced arm pivoted at its center. A coil housed in the
arm and a permanent magnet attached to the chassis
form a linear motor used both to track and to fast-feed the
pick-up across the disc. When the motor is energized, the
pick-up can be directed quickly to any track (<1 sec from
inner to outer track), and can follow the center of the
track accurately to within 0,1 um. Since there is only one
moving part (the arm pivot), the mechanism is extremely
reliable and wear is minimal. A feature of the CDM-9
pick-up is its simple diffraction-limited optics.
MDA.01408
128822
PCS 66 390