Hobart 120CU20, Operation And Maintenance Manual With Illustrated Parts List

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OM-2228 / Operation and Maintenance Manual
120CU20 / Series 500120 / 400 Hz. Generator Set
October 15, 2013 Chapter 2-4
Page 1
Section 4 Troubleshooting Procedures
1) General
The Troubleshooting Chart and Fault Code Chart located in this section cover the common faults and
malfunctions that you may find during operation or maintenance of this equipment. The charts may not
list all faults and malfunctions that may occur. If a fault or malfunction is not listed in the chart, start
looking for the cause at the source of power in the affected circuit. Refer to the schematic and connection
diagrams in Chapter 5. Test the circuit systematically until the source of the malfunction is isolated.
The Fault Code Chart is arranged under two headings: Commands and Faults. Commands display the
operation mode at the time a fault code is triggered.
The Troubleshooting Chart is arranged under three headings: Trouble Symptom and Condition, Probable
Cause, and Test Check and/or Remedy. Trouble(s), Symptom(s), and Condition(s) are described and
numbered. Probable Cause(s) are indented to the right and listed in numbered steps below Probable
Cause. Test Check and/or Remedy provides instructions for correcting the malfunction, and is listed
below each Test or Inspection procedure. Tests and inspections called for in the Troubleshooting Chart
are to be performed as described in Chapter 2, Sections 1-3, of this manual.
2) Equipment for Troubleshooting
WARNING
Exercise extreme care to avoid contact with high voltage leads and components.
High voltage can kill!
CAUTION
Maintenance personnel must be very careful when performing terminal-to-terminal
checks to be certain the proper terminals are being used, especially when using
jumper leads. Damage to electrical components may result from the application of
improper voltage and current.
A good quality multi-scale voltmeter is the only instrument required for troubleshooting. At least two
jumper leads with alligator, or similar clips, will be required. The engine electrical system may be
used as a 12 VDC power source.
3) Parts Replacement
To lessen end item down time, and to get a faulty machine back on line as quickly as possible, the black
box concept of parts replacement is reflected in the Troubleshooting and Fault Code Chart. For example,
if a component on a control box PC board is defective, the quickest way to remedy the situation is to
replace the complete PC board and send the old to stock. Some of the assemblies that tend to lend
themselves to this concept are:
•
Voltage regulator PC Board (REG)
•
Control PC board (CTL)
•
Engine Specific PC Board (ESB)
•
Engine Interface PC Board (EIB)
•
LED PC Board (LED)
•
28.5 VDC Transformer-Rectifier PC Board (TRB) [optional]