57 - "Mot" On Display (O). Excessive Wire Feeder Motor (404) Current; 61 - Mains Voltage Below Minimum Permitted; 73 - "Th0" On Display (O). Led (G) Lit. Diode Group (567) High Temperature; 74 - "Th1" On Display (O). Led (G) Lit. Igbt Group (548) High Temperature - Cebora SOUND MIG 3840/T Pulse Service Manual

CEBORA S.p.A.
In MMA mode it may also derive from an interruption in the output voltage detection line.
In any case, in addition to cleaning the torch, check:
– wiring between connector J13 of interface board (543) and output terminals (-)(BO) and
output (+)(BR);
– power wiring between end terminals of the transformer (531), diode group (567), and output
terminal (+)(BR);
– power wiring between transformer (531) central socket, choke (530), and output terminal (-)
(BO) of the power source.
If you find defective connections, fix and replace any damaged components.
If necessary, perform the tests for "open circuit operation", par. 3.5.8, and "operation on
resistive load", par. 3.5.9.
Replace control board (543) and/or transformer (531).

3.7.18 - 57 - "Mot" on display (O). Excessive wire feeder motor (404) current.

The motor control board (232) is equipped with a supply current limiting circuit for motor
(404), to protect any overload, and a circuit that detects when the limiter is continuously tripped,
indicating a permanent overload.
This overload is primarily due to mechanical causes, such as dirt in the gears of the
gearmotor, friction from a lack of lubrication, impediments in feeding the wire coil, bottlenecks
in the torch sheath along the torch cable, etc.
Therefore, clean the wire feed unit and check whether the problem continues to occur if
operating without the wire feeder. If so, you may hypothesize that the motor winding or
mechanical reducer built into the motor have deteriorated, and thus replace the motor (404).
If necessary, perform the "wire feeder motor operation" tests in par. 3.5.7.

3.7.19 - 61 - Mains voltage below minimum permitted.

The control board (543) checks for the "MAINS" (mains voltage presence) signal status,
coming from pre-charge board (562); if incorrect blocks the power source for error 61.
The signal can be checked on J7 of interface board (543):
mains voltage present (MAINS) = 0,1 Vdc, approx. on terminals 4(+) and 5(-).
−
Check the wiring between connectors J3 on pre-charge board (562) and J7 on interface board
(543), and if necessary, perform the MAINS CONNECTION TEST in par. 3.5.1, or replace the
pre-charge (562) and/or control (543) boards.

3.7.20 - 73 - "TH0" on display (O). Led (G) lit. Diode group (567) high temperature.

3.7.21 - 74 - "TH1" on display (O). Led (G) lit. Igbt group (548) high temperature.

With these alarms we recommend that you not shut off the power source, to keep the fan
running and thus cool the unit more rapidly. Normal operation is restored automatically as soon
as the temperature returns within the allowed limits.
− Make sure that the fan (512) is working properly (see par. 3.5.2).
− Check for proper air flow and make sure there is no dust or obstacles to cooling in the
aeration tunnel.
− Make sure that the operating conditions meet the specification values, especially observe the
"duty cycle".
− Check the wiring between J12 interface board (543), and thermostat (526) on the diode group
(567).
− Make sure that the thermostat (526) mounted on the diode group (567) is properly mounted
and in good working order; its contact must be closed at ambient temperature.
− Make sure that the thermostat board (551) is properly mounted on the igbt group (548); the
temperature signal transmitted to the control board (543) is PWM type, with duty cycle
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