Brother International MFC-7050C Service Manual - Page 120

Troubleshooting

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2. TROUBLESHOOTING 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. 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. 2.3 Checking prior to Troubleshooting Prior to proceeding to the troubleshooting procedures given in Subsection 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. Power requirements Check that: (1) The power supply specified on the rating plate located on the bottom of the machine is used. The supply voltage stays within the rating ±10%. (2) Each voltage level on AC input lines and DC lines is correct. (3) All cables and harnesses are firmly connected. (4) None of the fuses are blown. VI - 3

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2.
TROUBLESHOOTING
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.
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.
2.3
Checking
prior
to
Troubleshooting
Prior
to
proceeding
to
the
troubleshooting
procedures
given
in
Subsection
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.
Power
requirements
Check
that:
(1)
The
power
supply
specified
on
the
rating
plate
located
on
the
bottom
of
the
machine
is
used.
The
supply
voltage
stays
within
the
rating
±10%.
(2)
Each
voltage
level
on
AC
input
lines
and
DC
lines
is
correct.
(3)
All
cables
and
harnesses
are
firmly
connected.
(4)
None
of
the
fuses
are
blown.
VI
-
3