Komatsu PC200-8M0, Shop Manual

Page: 506 / 1254

200 General Information on troubleshooting
Symptom and troubleshooting numbers
40-200
2
PC200, 200LC, 220, 220LC-8M0
SEN06132-01
Symptom and troubleshooting numbers
(Rev. 2011/09)
k Park the machine on a level surface, lower the work equipment to the ground so that it is stable,
and stop the engine.
k When performing the operation with two or more service technicians, keep strictly to the agreed
signals, and do not allow any unauthorized person to come near.
k If the radiator cap is removed when the engine is hot, hot water may spurt out and cause burns, so
wait for the engine to cool down before starting troubleshooting.
k Be extremely careful not to touch any hot parts or to get caught in any rotating parts.
k When disconnecting wiring, always disconnect the cable from the negative (–) terminal of the bat-
tery first.
k When removing the plug or cap from a component which is under pressure of oil, water, or air, al-
ways release the internal pressure first. When installing measuring equipment, be sure to connect
it properly.
The aim of troubleshooting is to pinpoint the basic cause of the failure, to perform repairs swiftly, and to pre-
vent reoccurrence of the failure. When performing troubleshooting, an important point is of course to under-
stand the structure and function. However, a short cut to effective troubleshooting is to ask the operator
various questions to form some idea of possible causes of the failure that would produce the reported symp-
toms.
1. When performing troubleshooting, do not hurry
to disassemble the components.
If components are disassembled immediately af-
ter any failure occurs:
q
Parts that have no connection with the failure
or other unnecessary parts will be disassem-
bled.
q
It will become impossible to find the cause of
the failure.
It will also cause a waste of manhours, parts, or
oil or grease, and at the same time, will also lose
the confidence of the user or operator.
For this reason, when performing troubleshoot-
ing, it is necessary to perform thorough prior in-
vestigation and to perform troubleshooting in
accordance with the fixed procedure.
2. Points to ask the user or operator
1) Have any other problems occurred apart
from the problem that has been reported?
2) Was there anything strange about the ma-
chine before the failure occurred?
3) Did the failure occur suddenly, or were there
problems with the machine condition before
the failure?
4) Under what conditions did the failure occur?
5) Had any repairs been performed before the
failure? When were these repairs per-
formed?
6) Has the same kind of failure occurred be-
fore?
3. Check before troubleshooting
1) Check the machine for other symptoms of
failure.
2) Perform checks on items listed in "Checks
before starting".
3) Perform checks on other checking items.
4) Check other maintenance matters which can
be checked appearance and are considered
to be necessary.
4. Checking failure symptom
Check the extent of the failure by yourself, and
judge whether it is a real failure or a problem with
the method of operation, etc.
a
When operating the machine to reproduce
the failure symptom, do not perform any in-
spection or measurement that may make the
problem worse.
5. Troubleshooting
Use the results of the investigation and inspec-
tion in Items 2 to 4 to narrow down the probable
causes of the failure, then use the trouble-
shooting flowchart to locate the failure exactly.
a
The basic procedure for troubleshooting is as
follows.
1] Start from the simple points.
2] Start from the most likely points.
3] Investigate other related parts or informa-
tion.
6. Measures to remove root cause of failure
Even if the immediate failure is removed, the
same failure may occur again, unless the root
cause of the failure is repaired. To prevent this,
always investigate why the cause of the failure
occurred. Then, remove the root cause.