Komatsu BR380JG-1E0, Shop Manual, Page: 25 / 841

00 Index and foreword SEN01344-00
BR380JG-1E0
11
Handling electric equipment and hydraulic component 1
To maintain the performance of the machine over a long period, and to prevent failures or other troubles
before they occur, correct “operation“, “maintenance and inspection“, “troubleshooting“, and “repairs” must
be carried out. This section deals particularly with correct repair procedures for mechatronics and is aimed at
improving the quality of repairs. For this purpose, it gives sections on “Handling electric equipment” and
“Handling hydraulic equipment” (particularly gear oil and hydraulic oil).
Points to remember when handling electric
equipment
1.
Handling wiring harnesses and connectors
Wiring harnesses consist of wiring connecting
one component to another component, con-
nectors used for connecting and disconnecting
one wire from another wire, and protectors or
tubes used for protecting the wiring.
Compared with other electrical components fit-
ted in boxes or cases, wiring harnesses are
more likely to be affected by the direct effects
of rain, water, heat, or vibration. Furthermore,
during inspection and repair operations, they
are frequently removed and installed again, so
they are likely to suffer deformation or damage.
For this reason, it is necessary to be extremely
careful when handling wiring harnesses.
2. Main failures occurring in wiring harness
1) Defective contact of connectors (defec-
tive contact between male and female)
Problems with defective contact are likely
to occur because the male connector is
not properly inserted into the female con-
nector, or because one or both of the con-
nectors is deformed or the position is not
correctly aligned, or because there is cor-
rosion or oxidization of the contact sur-
faces. The corroded or oxidized contact
surfaces may become shiny again (and
contact may become normal) by connect-
ing and disconnecting the connector about
10 times.
2) Defective crimping or soldering of connec-
tors
The pins of the male and female connec-
tors are in contact at the crimped terminal
or soldered portion, but if there is exces-
sive force brought to bear on the wiring,
the plating at the joint will peel and cause
improper connection or breakage.