Check the focus, tracking movements are normal, normal laser emission, but the spindle motor does not turn. Analysis of the main reasons for the spindle motor does not turn many, but with the maintenance experience, the fault should be judged in the driving circuit, the spindle motor or power circuit. In addition, when the laser head component or its auxiliary circuit can also lead to the spindle motor does not turn.
According to the results of the preliminary examination, the possibility of damage of laser head is small, and the power circuit, the main drive circuit and the motor itself should be focused on.. The output voltage of the power output is normal, so the fault is judged in the main drive circuit or the 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. The reason of the analysis of the spindle motor is not the turn of the reason may be related to a certain part of the problem.
Firstly, the 1, 25 and 26 foot voltage of IC2071 (AN8482SP) of the main shaft driving circuit are measured, both of which are 2. Around 1V (the normal value is 9.3V).. There are two reasons for the low drive 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 from the spindle motor drive IC IC207116 foot feedback back spindle motor speed control FG pulse signal.
PG and FG two pulse signal by digital servo system and to count clock pulses and compared with a reference signal to detect rotation error data and the error data through D / a converter is the DC voltage, and control the spindle motor operation error signal voltage superimposed, from IC20012 pin output to the spindle drive the 12 foot of the integrated circuit IC2071. The driving circuit is controlled according to the variation of the error DC voltage, and the output voltage of 9.3V, and respectively from IC20711, 25 and 26 respectively.. When the need to stop, IC200134 pin output 4.9V to IC207115 pin, control spindle motor to stop.
From the above analysis, we should focus on the detection of IC207112 foot control voltage. During the laser search, the 12 foot voltage was 2.5V, normal. Note that the foot of the previous voltage are normal, should focus on the drive circuit and spindle motor. IC207119, 20, 21 foot 12V voltage and 13 foot 5V supply voltage are normal. Since the IC20711, 25, 26 pin voltage is only 2.1V (normally should be 9.3V) and its 12 pin input is normal, the fault is judged in the driving integrated block and its peripheral components or spindle motor. Detection of the peripheral components of the Holzer components, motor and IC2071 are normal, so suspected IC2071 damage. After replacing IC2071 (AN8482SB), troubleshooting.