Tweco 500P PowerMaster - Manual (Page 45)

POWERMASTER 500, 500P, 350
Manual No. 0-4749 5-3 SERVICE
5.02 Basic Troubleshooting Guide
A. Scope:
The troubleshooting guide is intended to be used by
qualified service technicians. The troubleshooting guide
contains information which can be used to diagnose and
correct unsatisfactory operation or failure of the various
components of the power source.
B. 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 instructions accordingly!
C. Troubleshooting Hints:
Examine connections for proper assembly and contact
before replacing a component. Wire lugs should be in tight
contact with the lead’s conductor and should be crimped
to the lead’s insulation. The mating surfaces of the
connection should be clean and free of oxidation. 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 disconnecting. Pulling
on wires for disassembly can damage 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.
All signals referenced in the following troubleshooting
guide can be measured with a digital multimeter (DMM).
WARNINGS
Disconnect the power source from the input
power source before carrying out any service
or repair work. Hazardous voltages can be
present in the machine whenever input power
is connected.
ALL SERVICE SHOULD BE PERFORMED BY
TRAINED PERSONNEL ONLY.
5.03 Troubleshooting Guide
This guide should be used as an aid to determine the cause
of a system malfunction or failure. It should be
remembered that in most welding situations there can be
a large number of variables which can affect the overall
system performance. These variables often include several
pieces of equipment, interconnect cables, weld cables,
shielding gas systems, grounding, consummable wire or
electrodes, part preparation, etc. It is important to check
all aspects of the welding system and environment when
troubleshooting a problem or malfunction.
Explanation of front panel lights (located under the
control panel door):
OUTPUT CONTACTOR ON – GREEN
This light indicates that either the OUTPUT CONTACTOR
switch on the front panel is on, or the remote GUN SWITCH
is on via either the 14 pin or 19 pin remote receptacle.
Whenever this green light is on, the machine should be
producing output.
OVERTEMPERATURE – AMBER
This light indicates that the machine has overheated and
shut itself off. When this light is on, the machine will be
disabled and not produce any output. After the machine
has cooled, this light will automatically turn off and the
machine will no longer be disabled.
The following guide lists several potential problems and
lists a number of items to check or possible causes.
DANGER:
ELECTRIC SHOCK CAN KILL
Open the main wall disconnect switch or
breaker, before removing any covers or access
panels on the welding machine. Live voltage is
still present even with the front panel control
switch OFF. Wait at least three full minutes
after power has been removed before removing
any covers or access panels to allow adequate
time for internal capacitors to discharge.