Hypertherm Powermax105, Troubleshooting Manual, Page: 103 / 180

Do System Tests to Identify Defective Components
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Powermax65/85/105 SYNC Troubleshooting Guide 810430 103
7. If the torch continues to not fire a plasma arc, and gas does not flow from the torch, do a check
for continuity between the torch and the plasma power supply, as follows:
a. Put the torch on its side. Remove the left side of the torch shell.
b. Do a check for continuity between pin 4 on the torch PCB (red wire) and pin 3 at J20
(Powermax65/85 SYNC) or J17 (Powermax105 SYNC) on the power PCB. Refer to
Figure 23 on page 104.
c. Do a check for continuity between pin 5 on the torch PCB (orange wire) and pin 2 at J20
(Powermax65/85 SYNC) or J17 (Powermax105 SYNC) on the power PCB. Refer to
Figure 23 on page 104.
d. If you do not have continuity between the pins, examine the DSP PCB. Continue with the
next step.
8. Set the power switch on the plasma power supply to OFF ( O ), and disconnect the power cord.
9. Remove the plasma power supply cover and the component barrier.
10. Disconnect the DSP PCB from the power PCB. Carefully remove the conformal coating from
the pins, if necessary. Too much of this coating can prevent a good connection with the power
PCB.
11. If the problem continues, replace the DSP PCB.
12. If the problem continues after a new DSP PCB is installed, replace the power PCB.