Lincoln LT-7 Troubleshooting Manual page 19

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Troubleshooting Guide –
components. See Wiring Diagrams for troubleshooting of specific circuits.
PROBLEMS
(SYMPTOMS)
When attempting to "cold start" the
wire does not stop feeding when it
touches the work piece.
The wire will not inch up. The wire
inches down properly.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln
Electric Service Department for electrical technical troubleshooting assistance before you proceed.Call 216-383-2531 or 1-800-
833-9353
TROUBLESHOOTING AND REPAIR
See Wiring Diagrams for location of specified
FIELD
COURSE OF ACTION
FUNCTIONAL PROBLEMS
1. Make certain a variable voltage
board is installed and connect-
ed correctly.
2. The jumper on the variable volt-
age board must be connected
to the "H" pin.
3. The logic board may be faulty.
4. The variable voltage board may
be faulty.
1. With LT7 at idle (not feeding
wire) observe light 1D on the
control board. The light should
be lit. If light is NOT lit the con-
trol board may be faulty.
2. While pressing the inch up
switch observe light 1A on the
control board. If light 1A does
NOT light check the inch up
switch and associated leads.
(#593 and #539) See wiring
diagram.
3. If light 1A is lit the control
board may be faulty.
LT-7 TRACTOR
RECOMMENDED SHOP
COURSE OF ACTION
1. Check lead #21 for continuity
2. Check lead #67 for continuity
1. Perform the Wire Drive Motor
CAUTION
Observe Safety Guidelines
detailed in the beginning of this manual.
(zero ohms) to "work".
(zero ohms) to electrode.
Test .
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