ESAB EPP-400 Manuel D'instructions page 294

section 6
problem
LED 12 – (red) Left –12V Missing
LED 12 – (red) Right –12V Missing
Very high Output current accom-
panied by either a left or right over
current (LED 6)
Over Temp Lamp illuminates
possible cause
Loose or unplugged P1 connector at
the left PWM / Drive PCB
Loose or unplugged P10 connector
at PCB1
Faulty left PWM / Drive PCB
Loose or unplugged P1 connector at
the right PWM / Drive PCB
Loose or unplugged P11 connector
at PCB1
Faulty right PWM / Drive PCB
Shorted IGBT
Current pot set too high
Faulty left PWM / Drive PCB
High remote current signal
Faulty PCB1
One or more fans inoperable
Broken wire or unplugged connector
at thermal switch.
Obstruction to air flow closer than 2 feet
(.61 m) to rear of power source.
Excessive dirt restricting cooling air
flow
Obstructed air intake
294
troubleshootinG
action
Secure P1 connector
Secure P10 connector
Replace left PWM / Drive PCB P/N 38030
Secure P1 connector
Secure P11 connector
Replace right PWM / Drive PCB P/N
38030
Replace the pair of IGBTs containing the
shorted IGBT
Lower the current setting
Replace left PWM / Drive PCB
Decrease remote current signal
Replace PCB1 P/N 0558038287
Repair or replace fan(s)
Repair broken wires and unplugged con-
nector
Allow 2 ft. (.61 m) minimum between the
rear of the power source and any object
that may restrict air flow.
Clean out excessive dirt, especially in the
extrusions for the IGBTs and freewheeling
diodes, the POS, NEG and Electrode Plates,
the main transformer (T1) and the filter
inductors (L1 and L2).
Check and clear any obstructions from the
bottom, front, and top rear of the Power
Source.