Samsung CLX-8640 series Service Manual page 260

4. Troubleshooting
b) Remove the main board shield. Measure the yellow motor power with DVM.
i) If 24V power is generated, replace the yellow toner supply motor(JC31–00159A).
ii) If 24V power is not generated,
• Measure the 24V power on the SMPS board. If the SMPS
(110V)) is defective, replace it.
• If the SMPS board is normal, replace the main board(JC92–02516A).
4-101
board(JC44-00150B (220V) / JC44-00149B
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