Tweco Thermal Arc TA 500 - Manual (Page 40)

Service 4-6 Manual No 0-0470
4.5 Troubleshooting Guide
If the TA-500 System malfunctions the troubleshooting guide
will be helpful in correcting the problem. Since the malfunc-
tion may be due to a faulty connection rather than a faulty
component, be sure to check all connections to a component
that appears to be malfunctioning.
The troubleshooting guide is arranged in the normal operat-
ing sequence of the system for easy reference. Each problem
has listed next to it the possible causes and the remedy.
In some cases the remedy is too complex to fit the table, in
which case there is a reference to one of the “Test Proce-
dures”.
4.6 Returns
If a product must be returned for service, contact your dis-
tributor. Material returned without proper authorization will
not be accepted.
4.7 Primary Voltage Selection
The TA500 transformers are manufactured for two volt-
age ranges. These ranges are specified on the Serial
Number Tag attached to the front of the unit. If the
voltage ranges must be changed, the proper connec-
tions are shown on the transformer terminal board.
4.8 Trouble-Shooting
Some of the circuitry of the Standoff Control can affect
the characteristics of the Power Supply and Torch, there-
fore it should be disconnected at the connection marked
POWER SUPPLY on the bottom left hand side of the
SC electronic unit inside the Power Supply. The jumper
connector, mounted to the wiring harness, should be
connected to the wiring harness connector. This will
avoid any interference of the Standoff Control while
troubleshooting the Power Supply. (See SC 504 instruc-
tion manual for trouble-shooting the Standoff Control).
A. No AC POWER Light on TAC 500.
1. Blown fuse or open circuit breaker at primary.
1. Replace fuse or reset breaker.
B. No AC POWER Light on Control Panel.
1. Supply Console cover interlock switch (SW5) not ac-
tuated or bad.
a. Check cover for proper installation. Replace
SW5 if bad.
2. Blown fuse (4Fu) in TAC 500.
a. Replace fuse.
C. No READY Light (Control Panel).
1. Coolant pressure switch PS2 in Supply Console open
(pressure below 75 psi/5.2 bar).
a. Check coolant level in HE200. Clean pump
filter screen. Adjust pump. Replace pump.
2. Pressure switch PS2 in Supply Console not satis-
fied.
a. Adjust (75 psi/5.2 bar) or replace PS2. (See
A, Section 4.8).
D. Gases do not flow when “ready” Light comes
on.
1. Gas supply not on.
a. Open valve.
2. Faulty post flow time delay (TD1).
a. Check TD1 (See B, Section 4.8).
E. Gases flow more than 2 seconds.
1. RUN/SET/PURGE switch in set.
a. Move to RUN.
2. Faulty post flow time delay (TD1).
a. Check TD1 (See B, Section 4.8).
F. Cannot set desired gas pressures.
1. Empty gas cylinders.
a. Replace.
2. Faulty gas regulator.
a. Repair or replace.
3. Faulty Solenoid Valve.
a. Replace.
When the START button is pressed, the gases and red
DC POWER Light should come on. If this does not
happen, check as follows:
G. Gas does not flow when START button is
pressed.
1. Faulty control relay 4CR.
a. Check relay (See C, Section 4.8).
2. START switch SW9 not closing.
a. Check for continuity when pressed.
3. No 24 volt power.
a. Check transformer T2.