OMTech 60 W Laser: Replacement HV Power Supply

The original HV power supply in the OMTech 60 W laser went casters-up just barely inside OMTech’s six month tube-and-supply warranty period. For the record, the laser controller reports this status info since mid-March:

Laser Stats - replacement supply
Laser Stats – replacement supply

I think the Total job laser on time line says the power supply failed after firing the laser for a little over eight hours. The OMTech manual says the laser tube should last 1000 to 2000 hours (low vs high power), which suggests I should stock up on power supplies.

Its replacement just arrived:

OMTech replacement HV supply
OMTech replacement HV supply

It (bottom) seems to be a knockoff of the original ZYE Laser supply (top), with a similar model number and a “serial number” resembling a date from last year. All the connectors matched up, which isn’t too surprising.

The three most interesting inputs:

  • L = controller’s active-low L-ON enable output
  • IN = controller’s PWM output
  • P = jumper to G (circuit ground) — not water flow sensor

Also note the two AC power-line terminals directly adjacent to the TEST button, then consider insulation and stand-off distances before poking the button with your index finger.

The power supply has a digital current meter, so I plotted output current against PWM input:

Laser Power Supply - mA vs PWM - overview
Laser Power Supply – mA vs PWM – overview

Taking more points at the low end, with vertical bars indicating single-digit flicker on the meter:

Laser Power Supply - mA vs PWM - 0 to 20 PWM
Laser Power Supply – mA vs PWM – 0 to 20 PWM

I have little reason to believe the meter reading indicates the true current with any accuracy and I know CO₂ laser output power does not scale linearly with the current.

But it’s cutting again, which is a step in the right direction.

5 thoughts on “OMTech 60 W Laser: Replacement HV Power Supply

    1. A man’s got to know his limitations …

      There’s no way to test the supply without hitching it up to a laser tube, which then becomes a $500 fuse. I’m pretty sure there’s a dead transistor / optoisolator along the enable circuit, but I admit to a morbid fear of dying.

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