Hypertherm HT4001 Plasma Arc Cutting System - Manual (Page 143)

MAINTENANCE
11-96
HT4001
Instruction Manual 6-17
Problem Possible Causes and Solutions
11. Gases and/or water continue
to flow.
11.1. One or more valves not closing.
All valves should close when in RUN mode (except SV1 if in N
2
mode). Check wiring using the system wiring diagram as
reference to troubleshoot.
12.1. There is no spark between the spark gap electrodes.
(Spark gap assembly is located in the RHF console)
Clean (with emery cloth), align, and/or re-gap (.020" per gap)
the electrodes, if necessary. Ensure that the electrode surfaces
between the gaps are flat. If surfaces are rounded, replace and
re-gap.
• Visually inspect the high voltage transformer T1 in the RHF
console for leaking oil or overheating. See Figure 7-8 for
location of T1. Replace T1 if leaking or overheating.
• Check for 120VAC at T1 after START command is given. Note
that door interlock switches S1 and S2 have to be closed in
order to pass the START sequence. Switch will close in both
IN position, and if pulled OUT.
• If there is no 120VAC at T1, use wiring diagrams and check
pins, connectors and associated wiring from T1 to relay board
PCB4 (see Figure 6-4 for detail of PCB4). If connections are
OK, there may be a problem with relay PCB4 or control board
PCB2.
• If there is 120VAC at T1, shut down system and remove
capacitors C5A and C5B in RHF console. Restart system and
see if a faint spark is now observed across the gaps.
• If a spark is not observed at the gaps, replace T1. If there is a
spark, shut down system, and replace capacitors C5A and
C5B. (Always replace the capacitors in pairs).
12.2. There is no high frequency at the torch.
Check for a shorted torch, a damaged nozzle lead, or loose lead
connections. Replace the torch or nozzle lead or tighten the
lead connections.
12. The POWER DC indicator
is illuminated, but there is
no high frequency and no
pilot arc.
Activate Plasma START
Select RUN
(with S2 on Gas Console)