Troubleshooting; Introduction; Precautions; Checking Prior To Troubleshooting - Brother MFC4820C Service Manual

8.2 TROUBLESHOOTING

8.2.1 Introduction

This section gives the service personnel some of the troubleshooting procedures to be followed if
an error or malfunction occurs with the facsimile equipment. It is impossible to anticipate all of the
possible problems which may occur in future and determine the troubleshooting procedures, so this
section covers some sample problems. However, those samples will help service personnel
pinpoint and repair other defective elements if he/she analyzes and examines them well.

8.2.2 Precautions

Be sure to observe the following to prevent the secondary troubles from happening:
(1) Always unplug the AC power cord from the outlet when removing the covers and PCBs,
adjusting the mechanisms, or conducting continuity testing with a circuit tester.
(2) When disconnecting the connectors, do not pull the lead wires but hold the connector
housings.
(3) Before handling the PCBs, touch a metal portion of the machine to discharge static
electricity charged in your body.
When repairing the PCBs, handle them with extra care.
After repairing the defective section, be sure to check again if the repaired section works correctly.
Also record the troubleshooting procedure so that it would be of use for future trouble occurrence.

8.2.3 Checking prior to Troubleshooting

Prior to proceeding to the troubleshooting procedures given in Section 8.2.4, make the following
initial checks:
Environmental conditions
Check that:
(1) The machine is placed on a flat, firm surface.
(2) The machine is used in a clean environment at or near normal room temperature (10°C to
35°C) with normal relative humidity (20 to 80%).
(3) The machine is not exposed to direct sunlight or harmful gases.
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