Chopper Module Boards Function Test Procedure - Lincoln Electric Fleet 650 Service Manual

LINCOLN ELECTRIC

CHOPPER MODULE BOARDS FUNCTION 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 help determine if the Chopper Module Boards are functioning properly and receiving the
correct input from the Output Rectifier Bridge and the Weld Control Board.
This test can only provide meaningful results if the machine is producing normal AC auxiliary output.
MATERIALS NEEDED
Volt/Ohmmeter
Frequency Counter or Digital Multimeter With Frequency Counter Function
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the Fleet 650 machine.
2. Perform the Case Cover Removal Procedure.
3. Perform the Chopper Module Capacitor Discharge Procedure.
4. Make sure that there is nothing plugged into the Amphenol receptacle.
5. Place the 'RUN / STOP' switch into the 'RUN' position.
6. Place the weld mode switch in the 'PIPE/GOUGE' position.
7. Start the engine and allow it to stabilize.
8. Locate the chopper module boards. See Figure F.13. See Wiring Diagram.
9. Visually verify the LED's on each board are illuminated according to Table F.4. See Figure F.14.
10. Using a volt/ohmmeter, check for 80 to 100 VDC at terminals B1- to B2+ and B4- to B5+ on each of
the chopper module boards. See Figure F.14. See Wiring Diagram.
11. If the correct DC voltage is not present at terminals B1- to B2+ and B4- to B5+ on the chopper
module boards, check for damaged conductors or faulty connections between the chopper module
boards, the output rectifier bridge and the stator weld winding. See Figure F.14. See Wiring
Diagram. Perform the Stator Voltage Test Procedure and the Output Rectifier Bridge Test
Procedure.
12. If the correct voltage is present at terminals B1- to B2+ and B4- to B5+ of the chopper module
boards, check for DC voltage at the chopper module board terminals B2+ to B3- and B5+ to B6-. If
voltage is present it should vary with a change in output commands from the output control
potentiometer.
13. Turn off the engine on the Fleet 650 machine.
Fleet™ 650 Service Manual
40