Samsung CLX-8640 series Service Manual page 258

4. Troubleshooting
a) Remove the rear cover after removing 7 screws.
b) Remove the main drive unit.
(Refer to 3.3.9. Main Drive Unit)
i) Rotate the gear by hand.
• If the motor operation is stiff, replace the motor(JC31-00149A)
ii) Measure the resistance value with DVM.
• If the measured value is out of the standard area (7~10 ohm), replace the motor(JC31–00149A)
c) If the motor is normal, measure the motor signal with DVM.
• If the phase output voltage is changed in 0~24V(8~10V), the output value is normal.
• If the phase output voltage is not changed to 0 or 24V, replace the main board(JC92–02429A).
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