The machine homes and moves, the job starts, but the beam does not fire — no cut, no etch — while the control reports the job is running.
These are the failure paths we see most often on the OMTech CO2 Laser for a laser not firing condition. Likelihood reflects field frequency; First Check is what you can do remotely before sharing logs.
| Cause | Likelihood | First Check |
|---|---|---|
| Lid or flow interlock open (safety switch or chiller flow sensor) | High | Confirm the lid closes fully and the chiller shows flow; check the interlock LED |
| Mirrors misaligned so the beam misses the nozzle | High | Do a tape test at each mirror and at the nozzle to see where the dot lands |
| Low tube current or HV supply fault | Medium | Read the mA meter during a fire command and compare to the set power |
| Wrong laser power parameter or paused output | Low–Medium | Check the cut setting, min power and whether the output is muted in software |
Work through these in order. Each step is something you can perform and report back on without opening the enclosure or swapping parts.
Confirm the lid is fully closed and the chiller reports flow. CO2 lasers inhibit firing on an open lid or lost coolant flow — a safety feature, not a fault to bypass.
Pulse at low power at mirror 1, then 2, then 3 and the nozzle, using masking tape to catch the dot. Where the dot drifts off-center is where alignment is lost.
Fire at a known power and watch the mA meter. Zero or very low current with a good command points to the HV supply or tube, not alignment.
Open the job and confirm min power, max power and that output is not paused or muted. A zero min-power setting on slow moves is a common 'no fire' cause.
After aligning mirrors to the nozzle center, run a small test square. A clean cut at the corners confirms the beam path; if not, re-check the interlock.
A CO2 that moves but will not fire is interlock, alignment or HV — and the tape test plus the mA reading tell us which. Never bypass the lid or flow interlock; that removes the only guard against exposure. Cross-reference the broader collections: No output / no fire · Laser optics & power.
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No. We guide alignment and confirm whether the tube or HV supply is at fault, then give you the part to swap — the swap is yours.
Only if the mA reads normal but there is still no beam after alignment and interlock checks. We confirm with the meter before suggesting a tube.
No. The interlock exists for eye and fire safety. We troubleshoot the switch, not around it.
Share the tape-test dots and the mA reading. We separate interlock, alignment and HV fault remotely so you change only what is broken.
Submit Your Case Connect With SpecialistsWe do not perform hardware repair, we do not replace parts, and we cannot promise a 100% resolution. Our role is limited to remote diagnostic and step-by-step guidance based on the information, photos and logs you share.
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