ESAB Precision Plasmarc EPP-450 Manual De Instrucciones página 44

section 6
problem
LED 12 – (red) Left –12V Missing
LED 12 – (red) Right –12V Missing
Very high Output current accompa-
nied by either a left or right over cur-
rent (LED 9 or LED 6 respectively)
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 t o a ir fl ow c loser t han 3 f eet
(1 m) to rear of power source.
Excessive dirt restricting cooling air
flow
Obstructed air intake
44
troubleshootinG
action
Secure P1 connector
Secure P10 connector
Replace left PWM / Drive PCB P/N
0558038324
Secure P1 connector
Secure P11 connector
Replace right PWM / Drive PCB P/N
0558038324
Replace the IGBTs
Lower the current setting
Replace left PWM / Drive PCB P/N
0558038324
Decrease remote current signal
Replace PCB1 P/N 0558038312
Repair or replace fan(s)
Repair broken wires and unplugged con-
nector
Allow 3 ft. (1 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.