Chapter 1 Troubleshooting; Initial Check - Brother HL-4040CN Service Manual

CHAPTER 1 TROUBLESHOOTING

1. INTRODUCTION
Troubleshooting is the countermeasure procedures that the service personnel should follow if
an error or malfunction occurs with the machine. It is impossible to anticipate all of the possible
troubles which may occur in future and determine the troubleshooting procedures, so this
chapter covers some sample troubles. However, those samples will help the service personnel
pinpoint and repair other defective elements.
1.1 Precautions
Be sure to observe and follow all the precautions to prevent any secondary problems from
happening during troubleshooting.
(1) Always turn off the power and unplug the power cable before removing any covers or
PCBs, adjusting the machine and so on. If you need to take voltage measurements with
the power switched on, take the greatest of care not to receive an electric shock.
(2) When connecting or disconnecting cable connectors, make sure that you hold the
connector body and not the cables.
(3) Electronic devices are sensitive to static build up; make sure that you touch a metal
portion of the machine to discharge yourself before accessing the PCBs.
Handle PCBs with care when repairing them.
Verify again that the repaired portion works properly.
1.2

Initial Check

Check the following items before attempting to repair the machine.
<Operating Environment>
(1) Put your machine on a flat, stable surface such as a desk that is free of vibration and
shocks.
(2) Use the machine in a well-ventilated room; use the machine within the following ranges of
temperature and humidity: temperature between 10°C and 32.5°C (50 °F to 90.5 °F), and
the relative humidity is maintained between 20% and 80%.
(3) Ensure the machine is not exposed to direct sunlight, excessive heat, moisture, or dust.
(4) Keep the machine horizontal when you carry it. To prevent injuries when moving or lifting
this machine, make sure to use at least two people.
Fig. 1-1
1-1