Filter
Top Products
SQUARE WAVE TIG 255
Return to Section TOC Return to Section TOC Return to Section TOC Return to Section TOC
Return to Master TOC Return to Master TOC Return to Master TOC Return to Master TOC
F-7
TROUBLESHOOTING & REPAIR
TROUBLESHOOTING GUIDE
Observe Safety Guidelines
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
The yellow light (PL1) on the front
panel is not lit.
One or more keypad lights (LEDS)
are dark and cannot be lit when
their respective keys are pressed -
machine is operable.
The Beeper (Piezoelectric Buzzer)
cannot be heard - machine operat-
ing normally.
POSSIBLE AREAS OF
MISADJUSTMENT(S)
1. Normal condition - this light
will glow only if machine is in
an overheated condition.
(Thermal overload).
1. Be sure that the proper weld
mode is selected. For
example, the high frequency
keys and keypad lights
(LEDS) are not active in the
stick mode.
1. Background noise may be too
loud for user to hear beeper.
RECOMMENDED
COURSE OF ACTION
1. Check the Keypad LED board
to the Control board harness.
The plugs may be loose or
defective.
2. If only one red LED won’t light,
the LED PC Board may be
defective. Replace.
3. If three or more red LEDS do
not light, the Control board may
be faulty. Replace.
1. Watch the Control Panel
Display to see if the keys are
responding properly to key
presses. If so then the Buzzer
may be defective. Replace the
Piezo Electric Buzzer. HINT-
The Piezo Electric Buzzer
may be checked by applying
a 9vdc signal to the buzzer
leads. Red lead to +. Black
lead to –.
2. The Control board may be
faulty. Check for the presence
of 15vdc at pins 6J6 to 13J6 at
the Control board. See figure
at end of this Guide. The 15vdc
will be present for a very short
period of time when a key is
pressed. If the voltage is not
present then replace the
Control board.
FUNCTION PROBLEMS
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric
Service Department for technical troubleshooting assistance before you proceed call 216-383-2531 or 1-800-833-9353.
CAUTION