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No observation, found that the disc rotation stops, then the display shows "NO DISC". The machine uses SANYO SF-101PN single row 16 line laser head, for many years, the estimated that the bald head may be aging. Clockwise tuning laser power adjustment potentiometer after fault condition has not changed. Due to the hands of the model with the laser head and trial Sony KSS-213V type laser head substitution test, can read part of the disc and playback pause more serious. Note that the original head is not completely aging, but other parts of the machine and other faults.wzvservice manual download site
Million with meter is used to measure power three terminal voltage stabilizing block 7808 input voltage for 12.03V, normal; output voltage 7.69V, low; 7805 input voltage for lO.05V, normal; output 4.71V, low. The two groups of power supply are used small 1N4007 diode bridge rectifier, analysis of the causes of failure for rectifier diode with the passing of time performance degradation, lack of capacity and lead to low output voltage. Try current larger 1N5408 diode will be the original 8 1N4007 diodes are replaced, and then measure the power supply voltage of two 7.93V and 4.94V, close to the nominal value. Test machine, reading and playing are normal. The original head for test machine, poor disk play pause seriously, but other normal sowing dish.
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