Hypertherm H401 Power Supplies - Manual (Page 41)

MAINTENANCE AND TROUBLESHOOTING
H401 & H601 Instruction Manual 5-3
5
Troubleshooting
Correct malfunctions of the solid-state control circuits by replacing the printed circuit boards.
Current control potentiometer not functioning:
• Jumper is positioned incorrectly. To adjust the current from the front panel potentiometer, place the jumper
between terminals 7 and 8. A remote potentiometer requires a jumper between terminals 8 and 9.
DC ON indicator (1PL) is illuminated, but there is no voltage:
• Contactor has failed.
DC ON indicator (1PL) is extinguished during the plasma start sequence:
• PAC500 plasma console is in “TEST” mode.
• DC ON lamp is burned out. If output voltage is indicated on the front panel voltmeter, the lamp is probably
burned out.
• Control relay CR1 has failed.
• There is an interface failure. Check the wiring to the PAC500 plasma console and console flow switches.
• The thermal switch is open. If the power supply has been operating above the rated output, the situation will
be corrected when the main transformer cools down.
Over-temperature indicator (2PL) is illuminated.
• A transformer or inductor thermal switch is open. If the power supply has been operating above the rated
output, allow the main transformer to cool down by letting the fans run for 5 minutes or longer before
attempting to cut again.
• Thermal switch failure. Thermal switches are normally closed and open when there is an over temperature
condition. Check switches and associated wiring.
Open circuit voltage present, but the arc does not start:
• Surge injection circuit has failed. Check resistor R1 and capacitors C13A and C13B. These components
are located across the power supply output. See the Parts List section to locate components.
• PAC500 plasma console high frequency generator or pilot arc circuits have failed.
Low output current and/or low open circuit voltage:
• A fuse is open in the 3-phase primary voltage supply.
• A transformer winding is open.
• Line voltage is low.