Carefully check the machine CD machine core circuit board, no exception. Analysis the machine into the drive circuit, when inserted into the CD disc, disc blocks the movement of the upper photoelectric tubes and a CD tube servo circuit of photoelectric signal pathway, CD machine core microprocessor detects the signal, the output load motor start signal, will make the loading motor CDS in the suction machine, because the disc can be inhaled, occasional and reading is normal, circuit is normal. Found the photoelectric tube surface dust is more, a cotton swab to wipe the surface of the photoelectric tube after commissioning, troubleshooting.aW5service manual download site