Hypertherm HT4400 HySpeed Plasma Arc Cutting System - Manual (Page 106)

MAINTENANCE
HT4400 Instruction Manual 5-15
2
Initial Checks
Before tracking down specific problems, do a visual check and verify proper voltages are present at the power
source, transformers and power distribution board.
1. Disconnect line power by turning main disconnect switch off.
2. Remove top plate, two side plates, front plate, and rear plate of power unit.
3. Inspect interior of power unit for discoloration on PC boards, or other apparent damage. If a component or
module is obviously defective upon visual inspection, remove and replace it before doing any testing.
Refer to the Parts List section to identify parts and part numbers.
4. If no damage is apparent, plug in the power supply unit, and apply power by turning on the main
disconnect switch.
WARNING
SHOCK HAZARD: Always use caution when servicing a power supply when plugged in and the
covers are removed. Dangerous voltages exist within the power supply which could cause injury
or death.