Hypertherm Powermax125 Service Manua - Manual (Page 158)

158 Powermax125 Service Manual 808070
8 – Troubleshooting and System Tests
Test 6 – Torch stuck open/torch stuck closed
Symptom: No fault occurs at power-up, but an 0-30 fault displays on the operator screen when attempting to fire the
torch.
Confirm that all of the proper consumables are installed in the torch.
In an idle (no start signal) working system with the torch and consumables installed, there should be continuity between
the dual black wires connected to the center post of the pilot arc IGBT and the red wire connecting to J28. With gas
flowing through the torch (gas test mode 1) there should be very high resistance between those 2 points.
 To set the system to gas test mode, display the service screen (refer to Displaying the
service screen on page 128), move the cursor to “G” (gas), and use the adjustment knob
to toggle to “1” (gas test mode). If air does not flow, the regulator might be faulty. Examine
the fault log to see if any 3-20-n faults are logged. (See
Run a gas test on page 130.)
Figure 27
Before continuing, turn OFF the power.
If the resistance value is always less than 100 Ω, remove the torch and recheck the resistance. If the value is still less than
100 Ω:
 Use an IGBT tester to check for a shorted pilot arc IGBT.
 Replace the pilot arc IGBT if it is shorted.
If the resistance is always greater than 100 Ω:
 Replace all consumables and recheck.
 If the resistance is correct (< 100 Ω) the old consumables are bad.
J27
WORK
LEAD
J26
RED
J18
ORG
J17
J32
J28
RED
J27
WORK
LEAD
J26
RED
J18
ORG
J17
J32
J28
RED
Gas test mode 0 Gas test mode 1
Black wires
Red wire (J28)
Continuous with the
nozzle or torch outer body
Continuous with system
negative
< 5 Ω > 10 kΩ