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SECTION 6
6.3.5 Fuses F1 and F2 Blown
Problem
Fuses F1 and F2 blown.
6.3.6 Intermittent, Interrupted or Partial Operation
Problem
Works OK at 250A or less- Over
current – Faulty Left Side
6-10
Possible Cause
Process controller ignites pilot arc
too soon after providing the
"Contactor On" signal
Faulty negative (Electrode) output
cable shorting to earth ground.
Shorted freewheeling diode.
One or more shorted diode
rectifiers (D13-D18) on "POS
Plate".
One or more shorted diode
rectifiers (D7-D12) on "NEG
Plate".
Possible Cause
Loose or unplugged connector at
left PWM/Drive PCB (PCB2)
Faulty left PWM/Drive PCB
Check voltage between P5-1 and
P5-2 at the left PWM/Drive PCB
(PCB2). Should be 20V AC.
Between P5-1 and P5-3 should
be 40V AC. If not the control
transformer (T5) is faulty.
ESP 400C and 600C Plasma Power Sources
Troubleshooting
Action
Process controller must allow at
least 300MS to lapse between
the application of the "Contactor
On" signal and the ignition of the
pilot arc. Fix process controller
logic and replace diodes.
Repair cable
Replace shorted freewheeling
diode and F1-F2
Replace all diode rectifiers on the
"POS Plate".
Replace all diode rectifiers on the
"NEG Plate".
Action
Secure connector
Replace right PWM/Drive PCB
P/N 38030
Replace control transformer T5
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