Mitsubishi Electric DD-6030 Service Manual page 18

7
Disc playback is NG (DVD).
Is PLL locked?
(Refer to waveforms.)
Y
Check signal process
system following to IC402.
Check peripheral circuits of
IC401 and IC306.
DVD RF signal
Fig. 1-3-17
CD RF signal
Fig. 1-3-18
N
N
Fig. 1-3-16
DVD RF signal
Pin 30 (TP502) of IC502
V : 500 mV/div
H : 50 ns/div
CD RF signal
Pin 30 (TP502) of IC502
V : 500 mV/div
H : 100 ns/div
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 IC401?
Y
Does RF output
higher than 1 V(p-p)
develop at pin 30 (TP502)
of IC502?
Y
Pin 43 of IC502 = 2.4V
Pin 44 of IC502 = 3.0V
Y
Check peripheral circuits
of IC502 and IC401.
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.
DVD playback waveform
CH1 : TP502 DVDRF 500 mV/div
CH2 : TP409 DVDPLCK
50 ns/div
Fig. 1-3-19
CD playback waveform
CH1 : TP502 CDRF 500 mV/div
CH2 : TP409 CDPLCK 5 V/div
100 ns/div
Fig. 1-3-20
N
Check peripheral circuits
of IC401 and IC306.
N
Check IC502.
Lens cleaning.
Pickup mechanism
replacement
DVD RF signal
Pin 30 (TP502) of IC502
DVD PLCK
Pin 117 (TP409) of IC401
5 V/div
CD RF signal
Pin 30 (TP502) of IC502
CD PLCK
Pin 117 (TP409) of IC401