MITSUBISHI DD5000
Service Manual

7
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? Y Y Check signal process system following to IC503. Does RF output higher than 1.5 V(p-p) develop at pin 45 (TP515) of IC501 ? Y N

Disc playback is NG (DVD).

N

Is PLL locked? (Refer to waveforms.)

N

Check peripheral circuits of IC502 and IC601.

Check IC501. Lens cleaning.

N

Pin 57 of IC501 = 2.4V Pin 58 of IC501 = 3.0V

Pickup mechanism replacement

Y Check peripheral circuits of IC502 and IC601. Check peripheral circuits of IC501and IC502.

Fig. 1-3-16

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 RF signal DVD playback waveform

DVD RF signal Pin 45 (TP515) of IC501 DVD RF signal Pin 45 (TP515) of IC501

V : 500 mV/div H : 50 ns/div

DVD PLCK Pin 117 (TP511) of IC502 CH1 : TP515 DVDRF 500 mV/div CH2 : TP511 DVDPLCK 5 V/div 50 ns/div

Fig. 1-3-17

Fig. 1-3-19
CD RF signal CD playback waveform

CD RF signal Pin 45 (TP515) of IC501

CD RF signal Pin 45 (TP515) of IC501

V : 500 mV/div H : 100 ns/div

CD PLCK Pin 117 (TP511) of IC502 CH1 : TP515 CDRF 500 mV/div CH2 : TP511 CDPLCK 5 V/div 100 ns/div

Fig. 1-3-18

Fig. 1-3-20

1-12