Flashing Diode (D1) & Field Diode (D2) Test Procedure - Lincoln Electric Fleet 650 Service Manual

LINCOLN ELECTRIC
FLASHING DIODE (D1) & FIELD DIODE (D2) 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 Flashing Diode (D1) & Field Diode (D2) are functioning properly.
MATERIALS NEEDED
Volt/Ohmmeter
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. Locate the flashing diode (D1) & field diode (D2). See Figure F.5. See Wiring Diagram.
5. Label and disconnect leads 232P, 232N, 232M and 204C from the flashing diode (D1). See Figure
F.6. See Wiring Diagram.
6. Label and disconnect leads 201A, 200A, 204B, 5H and 3A from the field diode (D2). See Figure F.6.
See Wiring Diagram.
7. Using a volt/ohmmeter, perform the forward voltage drop tests outlined in Table F.1 for each diode.
See Figures F.5 and F.6. See Wiring Diagram.
8. If any of the tests fail, the diode may be faulty.
9. If faulty, perform the Flashing Diode (D1) & Field Diode (D2) Removal And Replacement Procedure.
10. Connect the previously removed leads to the flashing diode (D1) & field diode (D2). See Wiring
Diagram.
11. Perform the Case Cover Replacement Procedure.
TEST POINT (POS)
TOP AC TERMINAL
BOTTOM AC TERMINAL
NEGATIVE TERMINAL
NEGATIVE TERMINAL
Table F.1 – Flashing diode (D1) & field diode (D2) resistance tests
TEST POINT (NEG)
POSITIVE TERMINAL
POSITIVE TERMINAL
TOP AC TERMINAL
BOTTOM AC TERMINAL
Fleet™ 650 Service Manual
EXPECTED READING
0.3 VDC – 0.7 VDC
0.3 VDC – 0.7 VDC
0.3 VDC – 0.7 VDC
0.3 VDC – 0.7 VDC
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