OKIDATA OF1050, Service Manual

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Service Guide OF1050/2350/2450
Chapter 7 Troubleshooting and Repair
Troubleshooting flow chart 5:
Printer Alarm 4
START
PRINTER ALARM 4 appears on the LCD display.
Power OFF, then power ON.
After a short delay, does "PRINTER ALARM 4" appear on the LCD display?
YES Remove the fuser assembly for testing (Refer to the Action Items Diagram). Check the
resistance between the thermistor contacts. At room temperature, it should read approximately
100 Kohms. (about 1.5 Kohms at high temperature).
Is the resistance correct?
NO Replace the fusing unit.
YES Does the thermistor contact correctly touch the contact assembly when the fusing unit is installed?
(Refer to the Action Items Diagram)
NO Adjust the contacts as necessary.
YES Refer to Action Item 10. Power OFF, then Power ON.
Does PRINTER ALARM 4 occur approximately 60 seconds after powering ON the unit?
YES Is the heater lamp of the fusing unit ON? To check, remove the stacker cover. Overide
the cover interlock. Light can be seen from the ends of the fuser when the heater lamp is ON.
NO Is the heater or thermistor open? Measure the resistance between the two
heater contacts. Normal resistance is approximately 0 ohms.
YES Replace the fusing unit.
NO Is the AC voltage from the fuser present at the contact assembly?
NO Replace the MCNT board. If the problem persists, replace the power supply
board.
YES Replace the fusing unit.
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