Samsung ML-1440, Service Manual, Page: 41 / 86

Troubleshooting
4-3 Samsung Electronics
4-1-3 Self Diagnostic Mode
If Error code occurs due to malfunction of the printer, perform Self Diagnostic Mode to solve the problem.
The printer works only in the self-test mode to solve the malfunction problem.
To enter the self-test mode, turn the power on pressing the buttons of [Down], [Shift] and [Stop] at the same time.
Release the button within 2 or 3 seconds if 78 shows in the DCU. If 00 shows in the DCU, press the button [Up] or [Shift]
to select the self+test , and press the button of [Enter] to operate. To stop, press the button of [shift] and [Enter] together.
00 Main Motor Operating System
Only the main motor is in operation.
01 Main High Voltage On(THV-)
-1400 voltage output by MHV terminal. Caution : High voltage probe should be used.
02 Transfer High Voltage(-)On(THV-)
-1000 voltage output by MHV terminal. Caution : High voltage probe should be used.
03 Transfer High Voltage (+)Reference on (THV +)
+800 voltage output by MHV terminal. Caution : High voltage probe should be used.
04 DEV/supply High Voltage : DEV/Supply High Voltage Test.
The left one of the three LEDs in the self-test panel is on when DEV high voltage Supply high voltage output
by each HV terminal(-500V). Press the [Up] button to switch the voltage. The middle and right one of the three
LEDs are on and -650 voltage output by DEV HV terminal.
Caution : High voltage probe should be used.
05 LSU Operating System
The scanning motor of LSU is in operation, the right LED of the three buttons on. Press the [Up] button to
Check LD. LD is functioning and the middle button is on. If the LD is normal, all LEDs are on.
06 Pickup clutch on
The Solenoid in the printer is in operation. To stop the operation, Press the button [shift] and [Enter] together.
07 Paper Empty(1st, SCF, MF) Sensor Test :
If activate the Actuator of the PEMPTY/PWIDTH Sensor, the left and right of the three LEDs are on.
Paper Empty Sensor (1st) ON/OFF 1st LED ON/OFF
Paper Empty Sensor (SCF) ON/OFF 2nd LED ON/OFF
Paper Empty Sensor (MP) ON/OFF 3rd LED ON/OFF
Increment DCU Code No. (08, Sensor TEST)
08 Feed & Exit Sensor Test
Test the Feed sensor and Discharge sensor in the same way as '06'.
09 Cover Open Sensor Test
The same way as code '06'.
10 Fuser Test
If the [Enter] button pressed, the right LED is on and temperature of the fuser is up to READY Mode. If the
[Up] button pressed, the middle LED is on and temperature of the fuser is up to Printing Mode.
If you press the button once more, the left LED is on and temperature of the fuser is up to overheat Mode.
11 Hot Burn Test
If the [enter] button pressed, the printer is continuously printing without detection.
Turn the power off to stop operation.
12 Cleaning Mode Print Mode
Print the paper to clean the OPC Drum in the Cartridge.