Open the machine shell, no disc conditions energized test machine, found many anomalies are as follows: (1) screen display brightness suddenly clearly suddenly dark instability; (2) laser head assembly without radial servo moving; (3) laser lens can focus the search; (4) power switch of a slight "squeak squeak" sound; (5) according to the out of the box key cannot be out of the box.

According to the failure phenomenon, the analysis thinks that the power supply should be checked first, and the internal contact of the power switch is found to be in poor contact. After changing the power switch, the screen brightness is stable, and the laser head module has a radial servo system, and the laser head can go up and down, but can not be out of the box. To test the dynamic loading disc test machine, capable of playing. From the above can not out of the box failure, analysis that the fault point should be in the export and import box circuit or tray. Because of the random circuit principle diagram, the author according to the physical mapping of the out and out of the box, see figure 1.

The analysis of the working process of the circuit in Figure 1 is as follows: IC601 (KS56C820 69) {30} and {31} are in low level. When the box key, the IC601{31} pin out of the box signal into a high level (about 4V), a box control signal through the resistance R906, R907 pressure driven transistor Q904 conduction, the transistor Q902 will guide, and out of the box motor M rotation, the tray body out of the box operation, simplifying principle figure 2. Into the box, IC601{30} foot into the box signal jump into a high level, with the same working principle of the box circuit, corresponding to the driving circuit of the box, Q903 and Q901 are all conduction, reverse to the motor M power supply, so that the tray into the box. The driving circuit power supply is provided by the 12V voltage regulator regulator Q910, ZD910 and resistance R910 to provide 5V power supply. The of the C is found to have no 12V voltage, so the 12V voltage of the Q910 is checked. Along the circuit board found that the copper clad copper wire part of the phenomenon of oxidation, respectively, with the lead wire.

Test machine, the box has been able to box but still can not enter the box, measured IC601{30} foot without voltage jump (always 0V), check Q903, Q901, etc.. Analysis of the IC601{30} foot may have open circuit phenomenon. Since the other functions of the IC601 are normal, the idea of considering the replacement of the more expensive IC601 block and the idea of repair.

Q903 and C in the e pole leads to two plastic soft wire, then a small button, you can achieve into the box. The author considers that the button is installed in the front panel of the PHONE or LEVEL Jack (so not used), the actual restructuring, the machine can be used normally, but the box can not be controlled by the remote control, and other normal.