Oki Microline 520 Service Handbook page 219

4.4.05 Common Problems
1. Nothing happens when the unit is powered on.
The unit may not be plugged in. Check the power cord connection to the outlet and to
the printer. If a power strip is being used, make sure that it is powered ON. Check to be
sure that an external fuse hasn't blown or that a circuit breaker hasn't tripped.
2. The printer does not print when the computer sends data.
The printer may be deselected. If the SEL light is out, press the SEL button to select the
printer.
The printer cable may not be securely connected. Check the cable to be sure that it is
properly connected to both the PC and the printer.
If you have installed the serial interface board, check to be sure that the board is firmly
seated in the printer.
3. A brand new ribbon has been installed and the printing is smeared and streaked.
The plastic shield on the ribbon is either loose or missing. The shield must be left on the
ribbon when you are installing the cartridge. To correct this situation, move the
printhead to the center of the platen (careful - the printhead may be HOT!) and lift off the
ribbon cartridge. Check the ribbon shield. If it is loose, secure it in place properly. If it
is missing, locate it and install.
4. Static electricity causes the paper to stick.
In cold, dry weather, static charges can build up on continuous-form paper. This can
make the paper cling to the paper separator. If you have this problem during
high-volume printing jobs, try moving the single sheet paper guides on the separator
together so that the paper rests on the guides rather than on the separator itself.
5. The Print Quality and Character Pitch buttons on the front panel won't work.
The Operator Panel Function Item on the printer MENU can be used to disable these
buttons. If the printer is part of a customized system or if it is used by a number of
people, the system manager may have used this option to make sure the printer is always
set properly.
NOTE:
This feature also prevents access to the Menu. To access the Menu, power OFF the
printer, then hold down the SEL key while powering ON.
Microline 520/521 Service Handbook
P/N 59257803
4 - 11 Failure Analysis