Weld Control Board Pwm Gate Signal Test Procedure - Lincoln Electric Fleet 400 Service Manual

LINCOLN ELECTRIC

WELD CONTROL BOARD PWM GATE SIGNAL 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 able to produce the PWM (Pulse Width Modulated)
gate signal needed to control the IGBTs (Insulated Gate Bipolar Transistor) on the Chopper Module Board.
MATERIALS NEEDED
Volt/Ohmmeter
Frequency counter or digital multi-meter with frequency counter function
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. Unplug any device that may be attached to the 6-pin Amphenol receptacle.
5. Place the weld mode switch in the 'CC-STICK' position.
6. Start the engine and let it run and stabilize.
7. Locate plug J3 on the weld control board. See Figure F.18. See Wiring Diagram.
8. Using the frequency counter, test for 20kHz PWM gate signal between leads 23+ (J3-10) and 25- (J3-
9) on weld control board. See Figure F.19. See Wiring Diagram.
9. If there is no 20 KHz gate signal, test for the presence of 80 to 100 VDC, at leads 13+ (J3-8) to 14-
(J3-16) of the weld control board. See Wiring Diagram.
10. If voltage is very low or not present, check leads 13 and 14 for faulty or damaged wiring or
connections between the weld control board and the chopper module board. See Wiring Diagram.
11. Using a volt/ohmmeter, test for 80 to 100 VDC at the terminals where the leads 13 and 14 connect
to the chopper module board. See Wiring Diagram. If there is no voltage at the chopper module,
perform the Output Rectifier Bridge Test Procedure and the Stator Voltage Test Procedure.
12. If the test fails, the weld control board may be faulty.
13. If faulty, perform the Weld Control Board Removal And Replacement Procedure.
14. Perform the Case Cover Replacement Procedure.
Fleet™ 400 Service Manual
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