REMARKS
1. Care of the disc drive
The disc drive requires no special maintenance.
It is, however, recommended to clean the objective
lens from time to time with a piece
of
wadding, dipped
in
alcohol.
2.
Set-up
of the Service Manual
The set is composed
of
various modules (A through
Z).
The circuit diagrams, PCB layouts and parts lists
have also been classified per module.
a)
Circuit diagrams
Of
each module a functional circuit diagram has been
given, with the incoming signals drawn as much as
possible
at
the left-hand side and the outgoing
signals at the right-hand side. Each incoming and
outgoing signal has a unique name, the meaning
of
which can be read
in
the Signal listing.
If a signal enters
or
leaves the module, this takes
place via a connector (e.g.
682
=pin 6
of
connector
82) and via a letter indication in the line. This
indication mentions
to
which module the line is
connected.
If the letter indication in the line is the same as the
module on which the signal is present, the signal
remains on the module mentioned and, naturally, no
connector is drawn.
b) Oscillograms and voltages in the circuit diagrams
-The oscillograms in the diagrams have been
measured with a
dual-beam
scope with Delayed
Timebase PM3214. The set has been connected
to
a monitor by means
of
a SCART cable
Video : still picture, picture number 5530
(EBU colour bar, 75% saturation)
Audio
1:
normal play, picture numbers 6200 -6500,
1 kHz modulation
Audio
2:
normal play, picture numbers 6500 -6900,
1 kHz modulation
-The DC voltages have been measured with a
Digital Multimeter PM2524, still picture, picture
number 5530, unless stated otherwise.
c) PCS layouts
Most modules
in
the set have been equipped with
doublesided copper pattern and plated-through holes.
For each module a PCB layout is drawn, consisting
of
a drawing
of
the component side and
of
the soldering
side (chip side) with corresponding copper pattern.
d) Parts lists
For each module an electrical parts list is given,
stating the service code numbers
of
the specific
electrical components that have been applied on
the module.
The code numbers
of
the standard components
(ICs, transistors, diodes, standard resistors, etc.)
have been placed on a collective list in Chapter
5.
e) Service code numbers
of
the modules
In this Service Manual service code numbers for
the modules have
not
been mentioned. Please
consult you parts supplier.
3. Repair
on
modules
To
enable repair/adjustment on modules use can be
made
of
extension PCBs
or
extension cables. A
survey can be found sub Service Tools
in
this chapter.
4. Hidden switches
On
Analog 1/0 module U two switches have been
applied, hidden for the user.
The function
of
these switches is :
SK1
: +
11
V
or
RC5
signal at pin 8
of
the Euro
connector.
Factory adjustment is RC5 at pin 8 (switch
pressed out).
SK2 : ENCODED CVBS
or
NOT ENCODED CVBS
signal on CVBS OUT connector BNC3. The
factory adjustment is ENCODED (switch
pressed out).
Please consult the circuit diagram
of
Analog 1/0
module U for more details on these switches.
5. The optical deck
The optical deck
in
the disc drive is composed
of
various critical components and at the production
department adjusted by complicated alignment
equipment.
For the time being repair
of
the Deck Electronics and
of
the Laser Detection Unit by a service technician is
not allowed.
If a failure analysis reveals that the Deck Electronics
or
LDU
are defective, the entire deck should be
submitted for repair to the production centre via the
Central Repair Procedure
of
the Concern Service
Centre. Please inquire at your parts supplier's for this
procedure.
Repairs on the slide drive assy and the Automatic Tilt
Control (ATC) assy are possible. See the List
of
mechanical parts
for
the correct code numbers.
6. Coding of items
The coding
of
component items in the service printing
of
the PCB's can differ from the coding
of
the items in
the circuit diagrams (exept supply module
T).
On
the
PCB's, a letter/number coding has been used (e.g. R1,
C1) and in the diagram a 4 number coding (e.g.
3001
,
2001
).
The table below shows the conversion
between both coding systems.
Circuit diagram
4 number coding
2 001
T-Citem
nbr
Lcomponent
nbr
:
1 = Unit, battery
2 =capacitor
3 = resistor
5 = coil, trafo, cristal
6 = diode
7 = transistor, IC
Service printing on PCB
letter/number coding
C1
TLitem
nbr
Lcomponent
letter:
=U
=C
=R
=S,L,K
=D
= T,TS,1,IC
CS 7 818
