Service manual

CEBORA S.p.A. 15
3.3.9 - In TIG, arc unstable, welding irregular.
NOTE
In TIG, the welding quality may not be acceptable due to current instability. In this case we
recommend switching to MMA operation, and performing welding tests.
MMA WELDING QUALITY TEST.
Correct?
 Power source in MMA, welding tests = good welding quality.
YES
NO
♦ Perform the “open circuit operation” test (par. 3.3.7) and “operation on resistive
load” (par. 3.3.8).
♦ Replace the power board (29).
♦ Check the condition of the torch and electrode. If necessary, sharpen the tip of the electrode.
♦ Check the presence and continuity of the gas flow (solenoid valve vibration) at the torch
output (see par. 3.3.5).
♦ Replace the power (29) and/or panel (26) boards.
3.4
- Error codes.
3.4.1 - Yellow led (G) lit = temperature above limits.
The thermostat is located on the dissipater of the power mosfets of the power board (29).
The power source delivers no current, but the fan remains in operation; we therefore
recommend leaving the power source powered in case of alarm for overtemperature.
Check the temperature of the dissipaters of the power modules on the power board (29), and if
necessary wait for them to cool completely. If the alarm persists, replace power board (29). If the
alarm is reset, check the efficiency of ventilation, make sure the ambient temperature is not too
high, and that the working cycle is not greater than the one specified.
3.4.2 - Yellow led (G) lit at the power source start-up = supply voltage above limits.
Alarm for high supply voltage, more than approximately 280 Vac, at start-up.
The power source delivers no current, but the fan (16) is supplied at the line voltage and may
be damaged in few seconds.
To restore proper operation, shut off the power source and restart with the correct voltage.
3.4.3 - Yellow led (G) lit + led (F) flashing = “Vs” voltage above limit.
3.4.4 - Yellow led (G) lit + led (E) flashing = “Vs” voltage under limit.
If the supply voltage of the internal driver circuits (Vs) exceeds the allowed limits during
operation, this check blocks the power source, with indication of led (F) or (E) flashing.
“Vs” voltage is generated by U2 on power board (29), and is measurable between terminal 2
of CN2 (-) and resistor R6 terminal close U6 (+). Rated value = 12.8 Vdc; alarm thresholds: <10
Vdc = led (E) flashing; >16 Vdc = led (F) flashing.
Proper operation is restored when voltage returns within allowed limits. If the Vs values are
not correct when the mains voltage is within the allowed limits, they can assume power board
(29) defective and so to be replaced.
3.302.212 12/01/06