everything was fine - fast, readable, worth the price
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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 Y Check signal process system following to IC402. Does RF output higher than 1 V(p-p) develop at pin 30 (TP502) of IC502? Y N
Disc playback is NG (DVD).
N
Is PLL locked? (Refer to waveforms.)
N
Check peripheral circuits of IC401 and IC306.
Check IC502. Lens cleaning.
N
Pin 43 of IC502 = 2.4V Pin 44 of IC502 = 3.0V
Pickup mechanism replacement
Y Check peripheral circuits of IC401 and IC306. Check peripheral circuits of IC502 and IC401.
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 30 (TP502) of IC502
DVD RF signal Pin 30 (TP502) of IC502