Solving High Voltage Power Supply Failure Problems

Kaiser LS402 repairs

23 lbs of trouble!  Each Kaiser LS402 high voltage power supply weighs 23 lbs and each one we have received for repairs has had different, nearly catastrophic failures…including components blown beyond recognition (see pics). 

The problems causing this damage have varied and include:

  • Internal voltage regulator failure
  • Failure of the HV output coils
  • Failure of the HV, High Frequency output filter capacitors
  • Failure of the internal switching power supply that set up the 24 VDC output for the Voltage regulators and the buss voltage circuit
  • High Voltage Power Supply Repairs

So why might you have trouble with this type of high voltage power supply?  As in the case of our Midwest U.S. laser technology customer, the reasons vary according to the age, condition, usage, and maintenance schedule for each unit.   For example, all capacitors wear out over time and usage.  Preventive maintenance service, which would include replace aging capacitors, would help lengthen the life of the power supplies.

How can you prevent this situation? Having the electrolytic capacitors (not just the HV HF) replaced periodically will help prevent serious damage in the long run. You should determine the frequency of this type of maintenance based on whether the machine often sits idle, or if it is used frequently. Have your HV power supply serviced at least every 3-4 years if it gets frequent use.

Are you hearing weird squealing sounds or resonance at high frequency? Warning! Catastrophic failure of your unit could be close at hand! If during use you notice any unusual voltage levels, odd sounds, or the unit begins to resonate, consider this a warning that your machine is in trouble and in need of service.  Take it off line immediately and send it in for service before the damage is unrepairable.

HV Power Supply Repairs

The cost of power supply repairs is usually far less that the cost of purchasing a new one, especially high voltage power supplies typically used for laser technology such as the Kaiser LS402 pictured. Having a test fixture on site at the repair center was invaluable allowing the service team to test each of these Kaiser LS402 power supplies with the actual load condition it would face in use as it fires the laser.

Test fixtures like this are comprised of components that are used in the actual laser application and allow the technicians to confirm that the power supply is fully repaired and operational under load before returning it to the customer.

The test fixture can include operation at low, medium, and high voltage output based on the acceptable range of the power supply. The test fixture can also be used to:

  • Make accurate HV in-line measurements
  • View and measure AC ripple & noise on DC HV
  • Measure absolute HV DC to 0.25% @ 25 PPM stability
  • View and measure Trise, Tfall, overshoot & settling time
  • Measure & monitor signals from 35Hz to 10MHz
  • View signals from DC to 20MHz

If you are searching for a repair center for your damaged power supplies or other industrial electronics, check first to see if your equipment is still under warranty and if so, contact the OEM about repairs. If it is out of warranty, contact an independent industrial electronic repair center to find out if they are a good fit for your company and your particular repair needs.They should offer free evaluations for your damaged equipment and, if needed, a free quote for repairs (no bench fees!). They should also provide repair reports if requested and a good warranty of at least one year that covers both parts and labor.

About the Author: ACS Industrial Services is an independent industrial electronic repair center providing repairs for all types of industrial electronic equipment and most all manufacturers including power supply repairs, circuit boards, drives, servo motors, CNC equipment, encoders, monitors and touchscreens, test equipment, and much more.  Rush Service is available and 2-Year Warranties cover most repairs.  The customer service team is available to answer your questions and help solve your industrial electronic repair problems. You can reach them by calling 800-605-6419 or going to