Tweco Hefty II CC CV Voltage Sensing Wire feeder - Manual (Page 33)

Troubleshooting Guide:
NOTES:
(1) Refer to the Connection and Schematic Diagram in the Diagrams chapter of this manual for
graphical assistance in disassembling and troubleshooting the wire feeder.
(2) The acceptable tolerance (in most cases) on resistance and voltage measurements made with
the DMM is
±
10%.
(3) Use only genuine replacement parts.
A. Unit is completely inoperative - nothing functions
Make sure all connections have been made to both the power source and wire feeder.
Make sure both the power source and wire feeder are turned ON.
Check 18 ga. wire connection on rear bus bar of the contactor for loose or faulty connections.
Check for a damaged power switch (S1).
Check for a damaged or tripped circuit breaker (CB1).
With input power supplied to the wire feeder, measure the DC voltage across the (+) and (-)
terminals of the bridge rectifier (CR1). The measured voltage should be within 5 volts of the
voltage on the output terminals of the power source.
If not, replace the bridge rectifier (CR1).
Check plug J1 on the motor control p.c. board for loose or faulty connections.
Replace motor control p.c. board if necessary.
B. Wire feed motor operates but wire does not feed or feeds erratically
Incorrect voltage/current and/or wire feed speed settings.
Make sure all connections to the wire feeder are tight.
Make sure feed rolls are tight.
ELECTRIC SHOCK can kill.
•
Follow all safety precautions.
•
Do not touch live electrical parts.
•
Turn OFF input power before servicing the machine unless otherwise noted.
•
Only qualified technicians are to service the machine.
CAUTION: Static sensitive devices.
•
Use static proof bags.
•
Use grounded wrist strap.
•
Use qualified personnel when testing or handling device.
430429-456
TROUBLESHOOTING
7-2 June 5, 2000 Revised