Similarly, if the focusing action is not normal, the focus signal and its output end of the peripheral components and the drive circuit can be detected. If the feed, focused without laser issued, you can consider substitution movement test, because of RF signal processing and laser emission control are integrated in the chip of movement.

The machine head reset to normal, and read dish disk can normal rotation, suspected head bad, but with the replacement of the new movement test machine, the fault persists.

Encounter this kind of problem, can be the first to use the oscilloscope to observe the RFL coupling capacitance c318, c319 eye diagram waveform is normal, if normal eye diagram waveform, focus on examination of DSP digital signal processing circuit; if there is no normal waveform, examine RF signal transmission path and the tracking control signal for the tracking drive signal in the head during the reset process is unable to see, only after the introduction of the focus in began to enter the tracking servo.

From the oscilloscope observation to read dish in the process is stable and clear eye diagram waveform output. Therefore, first check the DSP digital signal processing part. Know from the principle: when the laser head reset after the end of MNl03S26EGA, the output signal drives the focusing coil focus search, amplified by the driver, driving the lens moves up and down to adjust the focus, the laser emission, in a disk case, through the detection circuit generates a FOK signal into auto focus, MNl03S26EGA are also on the output spindle start at the same time, tracking control signal, RF signal processing circuit receives the reflected light into the focusing error signal and tracking error signal FE TE, to MNl03S26EGA, by means of the internal digital phase-locked loop circuit into the error data, the digital servo processing after focusing, tracking, feed and spindle control signal, so as to enter the automatic servo state.

The eye is normal but not read dish, this machine can enter the automatic servo, should focus on examination of MNl03S26EGA and its peripheral circuit. Measurement of MNl03S26EGA (100) pin digital phase locked loop circuit external input voltage of the filter capacitor, significantly low, the normal time should be about 1.5V. Doubt capacitor C313 leakage, remove the measurement is indeed damaged, the replacement of the fault.

Through the analysis and maintenance of the above examples of maintenance, can understand basic maintenance method Panasonic DU5 series movement of the disc reading process and its servo circuit.

In the hearts of Panasonic DU5. Boot after the first is feed circuit to drive the head assembly to the movement of the inner ring, when met feed limit switch, start focusing control, laser head focus on action, and a strong laser. In a disc, output spindle start and tracking control. At this time digital signal processing circuit to work, the disc began rotating into the normal disc reading process. If you have no disc, show "DISC NO"".

According to this principle, in the maintenance, if found on the boot, will soon show "DISC NO", then the fault should be judged mainly in the digital servo processing section. At this time into the disc to see if you can rotation, rotation, is the focus check tracking control; can not rotate, focus on examination of feed, focus, laser emission circuit and spindle control can in the head of the reset process carefully observe all the normal movements to make judgments.

In the boot, after a period of time to display the DISC NO, you can determine the fault mainly in the digital signal processing part. Can focus on RF signal coupling, FE, TE error signal and digital phase locked loop circuit.