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Panasonic DVD A300MU machine into, out of the warehouse is normal, but can not read the disk

Time£º2015-06-23 08:13:12  Source£ºNetwork  Author£ºUnknown  Clicks£º1379
  

 Check the focus and tracking movements are normal, normal laser emission, but the spindle motor does not turn. Analysis of the main reasons for the main shaft motor is not a lot of reasons, but with the experience, the fault should be judged in the driving circuit, the main motor or power supply circuit. In addition, when the laser head component or its auxiliary circuit may also lead to the spindle motor does not turn.eiyservice manual download site

According to the results of the preliminary examination, the possibility of damage to the laser head is small, and the power circuit, the main shaft driving circuit and the motor itself should be focused on. Measuring power output voltage is normal, so the fault in the spindle drive circuit or spindle motor. The figure is the machine spindle servo circuit diagram. When the disc placing in place, microprocessor IC6001 N64405FP control circuit for automatic detection, this head of focused search and emits laser. When the CPU detects focusing FOK signal, to the drive circuit issued a directive, the spindle motor rotation to read the disk directory. Analysis of the spindle motor is not the reason may be related to a certain part of the problem.
Firstly, the 1, 25 and 26 feet of the main shaft driving circuit IC2071 (AN8482SP) were measured, and the 2. Around 1V (normal value is 9.3V). There are two reasons for the low driving voltage: one is that the error control circuit is abnormal; the two is the driver IC itself.
The machine is driven by the error control voltage by the RF signal IC5001 AN8824FBP 64 output by 62 feet IC7001 AN8623FBQ, were compared by the PLL data connected and IC700114 feet outside the 27MHz clock frequency and microprocessor IC6001 internal obtained to control the operation of the motor spindle error signal and the spindle motor phase control PG pulse signal, respectively, from the IC700117, 9 feet output is sent to the servo processor IC2001 (the mn67700) of 75, 47 feet. IC200136, 37 foot external 40MHz crystal, its 45 foot is from the spindle motor drive integrated circuit IC207116 foot feedback to the spindle motor speed control FG pulse signal.