Lincoln LT-7 Troubleshooting Manual page 22

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Troubleshooting Guide –
components. See Wiring Diagrams for troubleshooting of specific circuits.
PROBLEMS
(SYMPTOMS)
The wire feeds at full speed in both
inch and weld modes.
The wire has limited or erratic
speed control in one or more
modes.
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. With the LT7 at idle (not feeding
wire) observe light 2F on the
logic board. If light 2F is lit the
control board may be faulty.
2. If light 2F is not lit the logic
board may be faulty.
1. Make sure the CV-VV switch is
in the CV mode. If the problem
is solved the variable voltage
board may be faulty.
2. The logic board may be faulty.
3. The control board may be faulty.
LT-7 TRACTOR
RECOMMENDED SHOP
COURSE OF ACTION
1. Perform the Wire Drive Motor
1. Perform the Wire Drive Motor
2. Check the wire feed speed con-
CAUTION
Observe Safety Guidelines
detailed in the beginning of this manual.
Test .
Test .
trol (R3) for resistance and
smooth operation. Normal
resistance is 5000 ohms.
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