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Service Guide ML393/ML393CPlus
Chapter 4 Failure Analysis
4.4.05 Common Problems
1. Nothing happens when the printer is powered ON.
Make sure the printer is plugged in.
Check the power cord connection to the printer and the outlet.
If a power strip is being used, make sure the strip is powered ON.
2. The ALARM lamp is lit.
The printer may be out of paper or the paper may have jammed. The SEL lamp will not light. After loading
paper, press the SEL switch.
The front cover may be open. Close the front cover.
The paper lever may not be set for the type of paper being used. Position the lever correctly.
If the ALARM lamp does not go out after paper is loaded, refer to Section 4.5 of this Service Handbook.
3. The printer does not print when the computer sends it data.
The printer may be deselected. Make sure that the SEL lamp is lit. If it is not, press the SEL switch.
Verify that the interface cable is correctly installed.
4. The paper keeps jamming.
Verify that the top of form is set so that the paper is held in place by the bail bar. If the top edge of the
page is below the bail, it will catch on the bail as it advances. Do not use the FORM FEED switch to load
paper into the printer.
If the paper does jam, power OFF the printer. Carefully back the paper out of the paper path by using the
platen knob. Remove any shreds of paper from the paper path.
5. The printer suddenly changes to unidirectional printing. It then stops printing completely. The MENU
light is flashing.
This indicates a Printhead Overheat Condition. When the printer prints for a long period of time, heat will
build up in the printhead. When the printhead temperature reaches approximately 115 degrees Celsius,
the printer will print unidirectionally. If the temperature continues to rise, printing will stop until the
printhead cools. Printing will resume after the printhead cools.
6. The ALARM lamp is blinking.
The bail is open. Close it.
The paper or ribbon is jammed. Clear the paper path. Thread the ribbon correctly.
The printhead cannot move. Clear the obstruction.
7. Static electricity causes the paper to stick.