Mitsubishi Electric DD-5000, Service Manual

Page: 16 / 76

1-12
Disc playback is NG (DVD).
Is PLL locked?
(Refer to waveforms.)
Check signal process
system following to IC503.
Check peripheral circuits
of IC502 and IC601.
Does pulse of
L = 1.65V and H = 3.3V
develop at pin 131 and
L = 0V and H = 1.65V
develop at pin 132
of IC502?
Does RF output
higher than 1.5 V(p-p)
develop at pin 45 (TP515)
of IC501 ?
Check IC501.
Lens cleaning.
Pickup mechanism
replacement
Check peripheral circuits of
IC502 and IC601.
Pin 57 of IC501 = 2.4V
Pin 58 of IC501 = 3.0V
Check peripheral circuits
of IC501and IC502.
7
Y
N
N
N
N
Y
Y
Y
DVD RF signal
Pin 45 (TP515) of IC501
V : 500 mV/div
H : 50 ns/div
DVD RF signal
DVD RF signal
Pin 45 (TP515) of IC501
DVD PLCK
Pin 117 (TP511) of IC502
CH1 : TP515 DVDRF 500 mV/div
CH2 : TP511 DVDPLCK 5 V/div
50 ns/div
DVD playback waveform
CD RF signal
Pin 45 (TP515) of IC501
V : 500 mV/div
H : 100 ns/div
CD RF signal
CD RF signal
Pin 45 (TP515) of IC501
CD PLCK
Pin 117 (TP511) of IC502
CH1 : TP515 CDRF 500 mV/div
CH2 : TP511 CDPLCK 5 V/div
100 ns/div
CD playback waveform
Fig. 1-3-16
Fig. 1-3-17
Fig. 1-3-19
Fig. 1-3-18
Fig. 1-3-20
PLL works as a servo loop to generate a clock signal for reading
RF signal binary data. With the PLL locked, the eye pattern is
identified clearly when triggered with the read clock PLCK.