Laser stopped cutting, lasering, firing in the middle of a job and will not pulse or fire. Laser Head still moves but does not burn
Preface: This article covers a few tests and checks for when your laser is not firing. Some of the tests are visual inspections while others will require you to change the machine configuration and run diagnostics
Quick Start Videos:
Use these videos to start the troubleshooting process. There will be more details and steps in the complete guide down below in this article.
Nova Overview
Nova 24 Components
Nova Overview
Nova 24 Components
Use this video to help location the Nova 24 LPSU, OPTO, Test Button and milliamp (ma) Meter
Complete Guide:
In the guide below there are many things to check that could indicate a particular failure, either in signal to the LPSU, the LPSU itself or even power to the LPSU. Many different checks need to be performed to rule out the non-causes.
Things to Check if the laser is not firing at all:
Power Switched ON
Contactor Engaged
Check Contactor
Power Switched ON
Please make sure Laser Power switch and Main Power switch are both in the On position (Flipped UP). Typically, if you try to run a project without the Laser switch in the on position you will also get a Water Protection Error since the chiller is powered up with the Laser Switch.
Contactor Engaged
The main contactor is located in the electronics bay on the right side of your machine behind the blue door(s). When you turn on the Laser Switch, the main contactor should engage (pull in) and make a bit of clunk noise. The main contactor powers the LPSU and the Chiller.
| Disengaged (Out) | Engaged (IN) |
Check Contactor
If the Main Contactor is not pulled in and you have both the Main and Laser power switches in the on position (Flipped Up) then the contactors function needs to be checked:
The Main contactor provides 120v power to your LPSU. If your Laser and Main switch are both in the on position but you do not have power indications on the LPSU, lets check the main contactor. Unplug the machine from the wall and check that the wires terminals on the Main Contactor are landed and tightened down.
Visual Checks:
Locate your LPSU based on the information listed here.
Nova 24
Nova 35, 51 and 63
Nova 24
Located on the left side of your machine behind the lower blue door.
Nova 24 LPSU Location | Example of the LPSU |
Nova 35, 51 and 63
Nova 35, 51, and 63
Located on the back of the machine, behind the blue door to the Left of the exhaust outlet
Nova 35,51, and 63 General Location | Example of the LPSU |
Use these visual cues to detect if power is present:
These are ok to use in lieu of a multimeter but they are only for positive confirmation of power and cannot be used to rule out that power is not present.
Nova 24
Nova 35, 51, and 63
Nova 24
You should have some LED's on the power supply that are illuminated. If you have the Chiller on and connected, the yellow LED for Water Protect (WP) should be illuminated.
Your Nova 24 ma meter is analog and you will not have a digital screen. Also check to see if the LPSU case fan is running.
Nova 35, 51, and 63
If the laser power supply is 'lit up' and/or shows something on the digital display, then it should have power. If you have the Chiller on and connected, the yellow LED for Water Protect (WP) should be illuminated.
Note: The machines before Apr. 2018 had been installed another type of laser power supply, like below.
Wiring Checks:
Wiring checks should be done with the power off and the machine unplugged from the wall with proper tools and personal protective equipment (PPE).
LPSU Wiring
Controller Wiring
LPSU Wiring
Check the terminations circled on the Opto Isolator Board for tightness. After tightening, test run the machine to check for laser output.
Controller Wiring
Locate the Ruida Controller on the right side of the machine in the electronics bay behind the lower blue door(s). After tightening, test run the machine to check for laser output.
Lets check that the green connector is fully seated and none of the wires are loose.
Connector is not Fully Inserted | Loose Wires | Correct Installation |
Checking Voltage With a Multimeter:
Use a multimeter to check the 120v power feeding the LPSU. Be sure to set your meter up properly and wear the proper PPE. You will be working with 120VAC.
Video Demonstration | Picture Demonstration |
On the 3 Pin plug, you will have a Brown L wire, Blue N wire and Yellow\Green Ground Brown to Blue - Should have ~120vac Brown to Yellow\Green - Should have ~120vac Blue to Yellow\Green - Should be ~0vac If you have 120V on Brown to Blue but the screen is not lighting up, or LEDS\Fans are off no matter what you do, then the LPSU is dead and needs to be replaced. |
Things to Check if the laser is firing but is weak or not cutting or engraving as expected:
Below is a list of things to check if your LPSU is showing that it is powered on and but not firing.
Material Settings
Material settings can have a huge effect on where the laser marks the material. If the power percent is set too low or the speed to high, you may not get an actual mark or what was supposed to be a cut looks like a score.
Check that you do not have your min power set too low to where the sharp corners and tight radii are not cutting. Up the min power level for the cut layer to be adequate for cutting the material for when the laser head is traveling less than 10mms.
Symptoms of a Bad cut | Example Layer Settings |
Corners and tight radius curves do not cut all the way or even fire at all (Back Side is shown here) | When the laser head is traveling 10mms (even is layer speed is set to 100mm/s) the Nova Laser will run the Layer Min Speed, in this case it is set to 1% which is too low to fire or cut the material |
Layer Speed Set to 25mms but on Corners and Tight Radius Curves, output is 1% | Example of Proper Settings for Reduced Power for Corner\Tight Radius Cutting |
Perform "Red Button Test"
Run this as a base test, it is one of the first tests you should perform. It will give a quick health check on your LPSU
Check your Laser Tube
Visually inspect the laser tube in the back of the machine
-Look at each end of the tube, checking for contaminants and signs of charring from the electrodes.
-Inspect the wiring to the tube for thermal insult or charring
-Inspect the tube for cracks. Carefully inspect the body of the tube looking for hairline cracks
-Inspect the tube for inner jacket failure. Your outer jacket should not be full of water, your tube is not an aquarium.
-Video the tube while it is firing, look for a steady beam through the center of the tube
Pulse Check At Tube Exit
Check that the beam output is not a Halo and is a dot and that it fires off a beam spot.
LPSU Current Check
Assuming that the Red button test was not abnormal, Run this current test and compare the results.
LPSU Check W/O Opto
If you got funky numbers in the LPSU Current test, it may be good to bypass the Opto board and re-run the test. Assuming that the Red button test was not abnormal, otherwise skip.
LPSU Check using Channel 2
You can run this test with or without the Opto bypassed.
If you got funky numbers in the above test, it may be good to try Channel 2 and re-run the test. Assuming that the Red button test was not abnormal, otherwise skip.
Check Alignment
If your Tube and LPSU pass the above tests, then they are making power and you just need to get that power to the material. Do a spot check on your alignment and check all 3 mirrors and your lens. We suggest pulling mirror 3 out of the laser head to check as it is dark inside the laser head.
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