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TROUBLESHOOTING & REPAIR
F-71 F-71
RANGER 305D
WARNING
WELD CONTROL FEEDBACK TEST
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 or
machine operator and will invalidate your factory warranty. For your safety and to avoid elec-
trical shock, please observe all safety notes and precautions detailed throughout this manual.
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 troubleshoot-
ing assistance before you proceed. Call 1-888-935-3877.
DESCRIPTION
This test will determine if the weld control PC board is receiving accurate current and voltage
feedback from the weld circuit.
This test will only yield usable information if the machine is producing some weld output.
MATERIALS NEEDED
Digital Multi-meter suitable for accurate readings in both the millivolt and normal weld
voltage ranges.
Resistive load bank
Ammeter,suitable for accurate readings of normal welding current. (Often built into the
load bank.
Wiring diagram
Control Inner-Connection diagram