Weld Control Board Feedback Test Procedure - Lincoln Electric Fleet 400 Service Manual

LINCOLN ELECTRIC

WELD CONTROL BOARD FEEDBACK TEST PROCEDURE

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 electrical 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 troubleshooting assistance before you proceed. Call 1-888-935-3877.
TEST DESCRIPTION
This test will determine if the Weld Control 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
Resistive Load Bank
Volt And Ammeter
Volt/Ohmmeter
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the Fleet 400 machine.
2. Perform the Case Cover Removal Procedure.
3. Perform the Chopper Module Capacitor Discharge Procedure.
4. Place the weld mode switch in the 'CC-STICK' position.
5. Make sure that nothing is plugged into the 6-pin Amphenol receptacle.
6. Connect the resistive load bank and the ammeter to the weld output terminals per the equipment
manufacturer's instructions; also connect the voltmeter probes across the weld output terminals.
7. Start the machine and apply a load of about 200 Amps, as shown on the external ammeter. If the
machine will not produce 200 amps, apply as much load as you can.
8. Using the voltmeter, measure and note the DC voltage at the weld output terminals.
9. Check the voltage between leads 204S+ (J6-1) and lead 208B- (J3-15) at the weld control board
Molex plugs. See Figures F.20 and F.21. See Wiring Diagram. The voltage should be the same as
was measured at the weld terminals.
10. If the voltage readings are different, check the wiring and connections between the welding
terminals and the weld control board. See Wiring Diagram.
11. Connect the millivolt meter probes between lead 206S+ (J6-2) and lead 204S- (J6-1). See Figures
F.20 and F.21. See Wiring Diagram. If the machine is currently producing 200 amps the millivolt
meter should read 25 millivolts.
12. If the machine cannot produce 200 amps of weld current, the correct millivolt signal will need to be
calculated by dividing the reading displayed on the external ammeter by 8. See the following
explanation.
Fleet™ 400 Service Manual
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