Universal Loader (Single Disc Tray Loader); Clean The Lens; Measure The Laser Current - Philips MCM7/22 Service Manual

Universal Loader
(Single Disc Tray Loader)
This document describes 2 versions, the version with the Mitsumi CD drive MCD2 and
the version with the Sanyo CD drive DA12 .
The CD drive used in a specific application is stated on the type plate, located on one
of the side walls of the changer module.
TABLE OF CONTENTS
Service Hints ....................................................................10-1
Pin description ..................................................................10-3
Blockdiagram.....................................................................10-4
Tray-motor Board ..............................................................10-5
Circuit Diagram CD Main Board .......................................10-6
Component layout CD Main Board ...................................10-7
Exploded View...................................................................10-8
Partslist .............................................................................10-9
MP3 CD03 Board (for orientation only).............................10-10
10-1
MP3 version, ICD03 PHONIC Layout stage .3
Service hints
In case of symptom „skipping tracks" perform
following actions:
1. VERIFY THE COMPLAINT
PLAYABILITY CHECK
use CD-RW Printed Audio Disk . . . . . .7104 099 96611
TR 3 (Fingerprint)
TR 8 (600µ black dot) maximum at 01:00
• playback of these two tracks without audible disturbance
playing time for: Fingerprint ≥10seconds
Black dot from 00:50 to 01:10
• jump forward/backward (search) within a reasonable time

2. CLEAN THE LENS

CD DRIVE – LENS CLEANING
Before touching the lens it is advised to clean
the surface of the lens by blowing clean air over
it in order to avoid that little particles make
scratches on the lens.
Because the material of the lens is synthetic and coated
with a special anti-reflectivity layer, cleaning must be
done with a non-aggressive cleaning fluid. It is advised to
use "Cleaning Solvent B4", available with codenumber
4822 389 10026.
The actuator is a very precise mechanical component
and may not be damaged in order to guarantee its full
function. It is advised to clean the lens gently (don't press
too hard) with a soft and clean cotton bud moistened with
the special lens cleaner.
The direction of cleaning must be in the way as indicated
in the picture below.
10-1

3. MEASURE THE LASER CURRENT

CD DRIVE – LASER CURRENT MEASUREMENT
The laser current can be measured as a voltage drop on
resistor 3822. Typical value 50mV (MCD2 disc drive) res-
pectively 55mV (DA12 disc drive).
D1
1.6V
F816
8
Vref_OPU
VREF_OUT
7
+ANALOG
VDDA1
3818
6
IREF
22K
5
VSSA1
D
4
SENSE
150mV CD DA
MONITOR 3
3871
180mV CD RW
MONITOR
2821
2
D
F819 EXTFILTER
F820 3822 F821 47n
1
+3.3V
LPOWER
1R0
LASER CURRENT
(mV = mA)
max 80mA (DA12) D
max 60mA (MCD2)
LASER
If the value is higher than 60mV (MCD2 disc drive) respec-
tively 80mV (DA12 disc drive) or the current increases just
after switching the laser on - the laserdiode is most probab-
ly defective. In that case the CD drive has to be replaced.
4. GENERAL HINTS
Since the HF pre-amplifier is integrated into the new "CD18"
signal processor the well-known eye pattern signal is not
available as external signal and cannot be measured any-
more. Also measuring the offset voltages is not necessary
because the new signal processor contains an automatic
offset compensation.
However the circuitry offers some new aspects for checking
the system:
- the Monitor voltage shows if the sensitivity is set correctly
(attention: ESD sensitive line!):
CD DA: 150mV
CD RW: 180mV
- the Focus search algorithm is divided into 4 steps:
st
1 step: CD DA sensitivity
nd
2 step: CD DA enforced sensitivity
rd
3 step: CD RW sensitivity
th
4 step: CD RW enforced sensitivity
The used sensitivity can be found out by either measuring
the Monitor voltage or counting the up/down movements of
the OPU until focus is found.
e.g. when a normal CD DA is played back Monitor voltage
should measure 150mV respectively Focus should be found
within the first up/down movement of the OPU.
In case a higher sensitivity setting can be observed than
defined, there are following possible reasons:
- disc scratched or dirty
- poor reflectivity of the disc - disc not conform standard
- lens of the OPU dirty
- laser power too low
80