Troubleshooting And Repair; How To Use Troubleshooting Guide - Lincoln Electric PRECISION TIG 375 Service Manual

F-2

HOW TO USE TROUBLESHOOTING GUIDE

Service and repair should be performed by only Lincoln Electric Factory Trained Personnel.
Unauthorized repairs performed on this equipment may result in danger to the technician and machine
operator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, please
observe all safety notes and precautions detailed throughout this manual.
This Troubleshooting Guide is provided to help
you locate and repair possible machine malfunc-
tions. Simply follow the three-step procedure list-
ed below.
Step 1. LOCATE PROBLEM (SYMPTOM). Look
under the column labeled "PROBLEM (SYMP-
TOMS). This column describes possible symp-
toms that the machine may exhibit. Find the list-
ing that best describes the symptom that the
machine is exhibiting. Symptoms are grouped
into four main categories: Output Problems,
Function Problems, Cutting Problems and LED
Function Problems.
Step 2. PERFORM EXTERNAL TESTS. The
second column, labeled "POSSIBLE AREAS OF
MISADJUSTMENT(S)", lists the obvious external
possibilities that may contribute to the machine
symptom. Perform these tests/checks in the order
listed. In general, these tests can be conducted
without removing the case wrap-around cover.
Step 3.RECOMMENDED COURSE OF ACTION
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs
safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before
you proceed. Call
HIGH VOLTAGE/ HIGH FREQUENCY can damage test equipment.
* Perform all voltage and wave form checks with high frequency circuit OFF. Perform
High Frequency Disable Procedure.
TROUBLESHOOTING & REPAIR
CAUTION
1-888-935-3877.
WARNING
PRECISION TIG 375
WARNING
The last column, labeled "Recommended Course
of Action" lists the most likely components that
may have failed in your machine. It also speci-
fies the appropriate test procedure to verify that
the subject component is either good or bad. If
there are a number of possible components,
check the components in the order listed to elim-
inate one possibility at a time until you locate the
cause of your problem.
All of the referenced test procedures referred to in
the Troubleshooting Guide are described in detail
at the end of this chapter.
Troubleshooting and Repair Table of Contents to
locate each specific Test Procedure. All of the
referred to test points, components, terminal
strips, etc., can be found on the referenced elec-
trical wiring diagrams and schematics. Refer to
the Electrical Diagrams Section Table of Contents
to locate the appropriate diagram.
F-2
Refer to the