Chopper Module Capacitor Discharge Procedure - Lincoln Electric Fleet 650 Service Manual

LINCOLN ELECTRIC

CHOPPER MODULE CAPACITOR DISCHARGE 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 procedure will ensure that the large Capacitors on each of the Chopper Module Boards have been
discharged. This procedure should be performed whenever work is to be attempted on or near the
Chopper Module Boards.
MATERIALS NEEDED
Volt/Ohmmeter
Resistor (25-1000 ohms and 25 watts minimum)
Electrically Insulated Gloves
Electrically Insulated Pliers
Jumper Leads
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the Fleet 650 machine.
2. Perform the Case Cover Removal Procedure.
3. Locate the two chopper module boards on the choppers and choke bracket. See Figure F.3. See
Wiring Diagram.
4. NEVER USE A SHORTING STRAP TO DISCHARGE CAPACITORS. If the Lincoln recommended resistor
or an equivalent resistor is used, the capacitors can be discharged by holding the resistor with
insulated gloves and insulated pliers and using the resistor terminals to bridge chopper module
board terminals B1 to B2 and B4 to B5 on each chopper module board. DO NOT TOUCH THE
TERMINALS OR METAL PARTS OF THE PLIERS WITH YOUR BARE HANDS. Hold the resistor in place
for about ten seconds. If another type of resistor is used, jumper leads may need to be attached to
the resistor. See Figure F.4. See Wiring Diagram.
5. Using a volt/ohmmeter, check the voltage across terminals B1 and B2 then across terminals B4 and
B5 on each chopper module board. See Figure F.4. See Wiring Diagram. Voltage should be zero.
6. If any voltage is present on either chopper module board, repeat step 4 until reading is zero volts.
7. Perform the Case Cover Replacement Procedure.
Fleet™ 650 Service Manual
19