Samsung WC-M15i Series Service Manual page 71

Troubleshooting
Error code 3-020
Fault Scanner Error
Description
The feeding paper is stopped in the front of transfer roller and all lamps on the operator panel blink.
Check
1. LSU
2. Engine board
Cause
1. Defective LSU
2. Defective Q5, or CPU
3. Abnormal resistance value of R8, R62
Solution
1. Perform DCU diagnostic code 05. If the DCU error code 95 is displayed, replace LSU.
If you cannot solve the problem after you replace LSU, follow the steps below.
(1) When you press ENTER key with DCU code '05', if the LSU motor does not run, check U205
pin 5, pin 6. If U205 pin 5, and pin 6 are normal, check CPU pin 40 and the related parts.
If the motor drives properly, and CPU pin 25 is not below 0.5V, replace R51 and CPU.
(2) When you press UP key with DCU code '05', if ON and OFF lamps do not turn on, check CPU
pin 28 and 41, and their related parts. Normally pin 28 is over 3.5V when high, and below 0.7V
when low. If the transformer works normally, replace CPU.
Remark
Others
Q3, U3, CN3, SW151
5-34
Model ML-6100
Samsung Electronics