JLG 3969electric ANSI Service Manual User Manual
Page 31
SECTION 3 - TROUBLESHOOTING
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3-1
SECTION 3. TROUBLESHOOTING
3.1
GENERAL
This section contains troubleshooting information to be
used for locating and correcting most of the operating
problems which may develop. If a problem should
develop which is not presented in this section or which is
not corrected by listed corrective actions, technically qual-
ified guidance should be obtained before proceeding with
any maintenance.
3.2
TROUBLESHOOTING INFORMATION
1.
The troubleshooting procedures applicable to the
aerial platform are listed and defined in Tables 9-1
through 9-4. As an aid to table use, the aerial plat-
form is divided into four major groups, each covered
separately within this section. These groups are as
follows: elevation system, chassis assembly,
hydraulic system and electrical system.
2.
Each malfunction within an individual group or sys-
tem is followed by a listing of probable causes which
will enable determination of the applicable remedial
action. The probable causes and the remedial action
should, where possible, be checked in the order
listed in the tables.
3.
It should be noted that there is no substitute for a
thorough knowledge of the equipment and related
systems.
4.
It should be recognized that the majority of the prob-
lems arising in the machine will be centered in the
hydraulic and electrical systems. For this reason,
every effort has been made to ensure that all likely
problems in these areas are given the fullest possi-
ble treatment. In the remaining machine groups,
only those problems which are symptomatic of
greater problems which have more that one proba-
ble cause and remedy are included. This means that
problems for which the probable cause and remedy
may be immediately obvious are not listed in this
section.
5.
The first rule for troubleshooting any circuit that is
hydraulically operated and electrically controlled is
to determine if the circuit is lacking hydraulic oil and
electrical control power. This can be ascertained by
overriding the bypass valve (mechanically or electri-
cally) so that oil is available to the function valve,
then overriding the function valve mechanically. If
the function performs satisfactorily, the problem
exists with the control circuit.
3.3
HYDRAULIC CIRCUIT CHECKS
The reference for improper function of a hydraulic system,
where the cause is not immediately apparent, should be
the Troubleshooting Chart. The best place to begin the
problem analysis is at the power source (pump). Once it is
determined that the pump is serviceable, then a system-
atic check of the circuit components, beginning with the
control, would follow. For aid in troubleshooting, refer to
the Illustrated Parts Manual for hydraulic diagrams of the
various circuits.