Hypertherm Powermax125 Service Manua - Manual (Page 159)

Powermax125 Service Manual 808070 159
8 – Troubleshooting and System Tests
 If the resistance is still greater than 100 Ω, measure the resistance in the torch between the pilot arc wires (pin 1
or 2) and negative arc power (the center connection).
 If the resistance is still too high, replace the torch and lead.
 The retaining cap should be snug but not overtightened.
 All values are ±50%. However, this range is intended only for reference. Resistance
values can vary widely depending on the type of multimeter and the polarity used to
measure the readings.
Check the function of the pilot arc IGBT:
 Turn the machine OFF and disconnect the power.
 Install a jumper wire (at least 8 AWG) from the work lead (J27) to the pilot arc IGBT (dual black wires).
 Reconnect the power and turn on the machine.
 Attempt to fire the torch.
 If the torch fires, replace the pilot arc IGBT.
Figure 28
J27
WORK
LEAD
J26
RED
J18
ORG
J17
J32
J28
RED
Install a test jumper here