Service Hints - Philips MZ-1000 Service Manual

Service Hints

In case of symptom „skipping tracks" perform
following actions:
1. VERIFY THE COMPLAINT
PLAYABILITY CHECK
Use CDDA SBC 444A: . . . . . . . . . . . . . .4822 397 30245
TR 14 (600µ black dot) maximum at 01:15
TR 19 (fingerprint)
TR 10 (1000µ wedge)
Use CD-RW Printed Audio Disk . . . . . . .7104 099 96611
TR 3 (Fingerprint)
TR 8 (600µ black dot) maximum at 01:00
• playback of all these tracks without audible disturbance
• jump forward/backward 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 "KODAK LENS CLEANER CAT 176 71 36", available
in normal photo shops.
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.
10-2
3. MEASURE THE EYE-PATTERN SIGNAL
EYE-PATTERN SIGNAL – JITTER MEASUREMENT
Measure the signal direct on resistor 3898 using an
oscilloscope (see also chapter 10-9).
V_HF
HF-Amplifier
2,1V
2883 3903 3904
D
470n 2K2 2K2
1,7V
7881
R
BC847B
1V
D
0,7V
7877
BC847B
D D D
See below examples of the signal. Amplitude should read at
least 700mVpp using SBC444A.
If the oscilloscope shows a signal like the 'bad' one, and/or
the amplitude decreases within 1minute - the CD drive has
to be replaced.
3895
+3.3V
6 IREF
33K
D
SIGNAL PROCESS
3896
5 VDDA1
100R
D
D
4 VSSA1
D
1,5V
3 ISLICE
1,5V
2813 3898
2 HFIN
HFIN
6n8 180R
1 HFREF
2816
D
LDON
1,5V
22n
64
3899
2,1V
10K
7878 for CD_DA : 0V
for CD_RW: 3V
BC847B
D
EYE-PATTERN
InnerSW
from 1801
3970
STBY
1K0
to 7801
TB = 0.5µs/div
good
bad
END
FRONT
INTERFACE
VERSATILE
63 62 61
+3.3V
7803
BC847C
D