Tweco Hefty II CC CV Voltage Sensing Wire feeder - Manual (Page 32)

TROUBLESHOOTING
Scope:
The troubleshooting guide is intended to be used
by qualified service technicians. The troubleshoot-
ing guide contains information which can be used to
diagnose and correct unsatisfactory operation or
failure of the various components of the wire feeder.
Each symptom of trouble is followed by a list of
probable causes and the procedure necessary to
correct the problem.
Safety:
To ensure safe operation and service, read this
entire manual before attempting to service or repair
this machine. The service technician may be asked
to check voltage levels while the machine is turned
ON; to assure safety, use care and follow all instruc-
tions accordingly!
Troubleshooting Hints:
Examine connections for proper assembly and
contact before replacing an electrical component or
printed circuit board. Wire lugs should be in tight
contact with the lead’s conductor and should be
crimped to the lead’s insulation. The mating sur-
faces of the connection should be clean and free of
oxidation.
Before replacing a suspect printed circuit board,
disconnect all wire plugs from the printed circuit
board. Then, firmly reconnect all wire plugs to the
printed circuit board and retest the machine to see
if the problem persists. Faulty connections or wiring
problems are often the cause of an equipment
malfunction!
Do not pull on wires to disassemble connections.
Firmly grasp each lug or connector when discon-
necting. Pulling on wires for disassembly can dam-
age the integrity of the connection and cause future
malfunctions.
Prior to disassembly or servicing of the machine,
note the wiring and connections in the machine.
Reassembling should place the wires in the same
location and routing as received from the factory.
Keep wires and leads away from hot parts and
sharp objects.
Most of the printed circuit boards in the machine
contain static sensitive devices. Use a grounding
strap or other suitable grounding means before
attempting to service or make measurements on
printed circuit boards.
All signals referenced in the following trou-
bleshooting guide can be measured with a digital
multimeter (DMM).
430429-456
TROUBLESHOOTING
June 5, 2000 Revised 7-1