Waveforms Of Cd Circuit - Sharp MD-R3H Service Manual

1 2 ,
IC700
100
2V/1mS (DC range)
[Disc playback mode]
Potential difference 0V
Disc free from flaw
Disc having flaw
(the same as above) 100
90
Potential difference 0V
If a flaw exists, pulse-like
noise appears as shown
right.
10
Noise appears also in
output of and TE or
FE signal.
,
IC700
11 12
100
0.5V/0.5mS
90
(Dc range)
[Disc playback mode]
Potential difference 0V
10
9
IC750
100
50mV/2mS
90
[Disc playback mode]
1/2VCC
10
0%
3
TP751
100
0.2V/0.5µS
90
(AC range)
[Disc playback mode]
10
0%
TP751 4
100
0.2V/1mS
90
(DC range)
In test mode 3
1/2VCC
10

WAVEFORMS OF CD CIRCUIT

90
10
0%
0%
0%
0%
0.2V/1mS (DC range)
[Disc playback mode]
1/2VCC
IC750 22
In test mode 2
(disc is not loaded.
Lens is moved up and down.)
1/2VCC
200mV/0.5S (DC range)
* Observation with the aid
of storage oscilloscope
Only the triangular wave
and luminous dot shown
right are observed on oscillograph.
,
IC800 37 38
Disc motor
PWM output
0.2V/10µS
(DC range)
[Disc playback mode]
(Use the 10:1
probe.)
IC800 19
20mV/0.5µS
(AC range)
[Disc playback mode]
(Use the 10:1 probe.)
IC800 28
2V/0.1µS (DC range)
[Disc playback mode]
4
IC800
2Vdiv (DC range)
Playback mode, 4.8V
Stop mode, 0V
When the disc rotates and
the HF signal is
synchronized with the IC
internal signal, H level is
set.
– 59 –
100
90
10
0%
TRIG
100
90
10
0%
100
90
PWM1
GND
PWM2
10
0%
GND
100
90
10
0%
100
90
GND
10
0%
* If disc has flaw or during track
search pulse-like "L" level appears
as shown below.
100
90
10
0%
MD-R3H