View Full Version : Troubleshooting ULS 25E laser

Colin Jenkins
12-25-2010, 6:24 PM
I have an old ULS 25E that I use occasionally. It is difficult to get any tech help for it from ULS. I have a problem recently where the machine will randomly go into 'initializing' mode and stops engraving and restarts itself. I'm wondering if anyone has had a similar problem and might have an idea what the cause is. At the direction of a laser tech company that I use for tuneups, etc, I have replaced the printer cord, reloaded the software and replaced the on/off switch. I was advised by a PC tech that we use that when this happens to a PC, it's almost always the power supply. I put a voltmeter on the power supply and got a 24V reading which is what it is supposed to be outputting. I'm not really sure how to troubleshoot the power supply beyond that.

If anyone else had this problem and could shed some light on what to try next, I'd appreciate it. Compared to buying a new machine, I feel I'm money ahead if I can repair this one to keep it running.

mike berry
12-25-2010, 7:51 PM
Mike McKenzie from CEM Lasers. He's in CA and if this guy can't fix it, nobody can!


Mike Null
12-26-2010, 6:32 AM
I agree that Mike is the guy to call but continue to look at your connection and re-connect the cable at both ends. This is likely a communication problem.

Kay Bengtson
12-26-2010, 12:16 PM
Mine is sensitive to power fluctuations, so I have to be careful about running other machinery that can cause power sags. I already have it on a surge protector but dips in voltage cause problems. It just loses registration and the stepper drives the head to one side or to a random place. I have also found that sometimes the computer can send a corrupted file that causes issues like this. That can be caused by a RAM error.


Rob Bosworth
12-27-2010, 1:57 PM
Colin, that system should have a power supply that is outputting 28 VDC. If it is only putting out 24 VDC, you have a failing power supply.

Mike Mackenzie
12-27-2010, 5:16 PM

A couple of things to try or check.

Check the printer mode in the computer bios it should be set to Standard or ECP.

Re seat the memory simm on the mother board, Maybe even replace it to be sure you do not have bad ram.

Up plug and re plug all of the connections to the mother board.

Also Rob is correct the power supply should be 28VDC and you should check it under a load print a solid black rectangle set the power to 100% 10 speed, 1000 ppi, 1000 dpi.

Just let it run on the aluminum table check the power before you start and then 10 minutes after you start. If you use alligator clips you can attach your meter to the power supply and then check it while it is running. It should not drop in voltage if it does try blowing the supply out with compressed air then run the test again.

If the power still drops then you more than likely have a power supply that is going bad.

Always remember to UN plug the system when working with the power supply.

Colin Jenkins
12-28-2010, 2:50 PM
Hi Mike, I had been avoiding contacting you for this problem because I know how busy you have been so I appreciate your chiming in. I typed 24V but I meant 28V but I haven't checked it under load as you suggest. When you refer to the simm on the mother board, are you talking about the motherboard of the engraver or of my PC?

Mike Mackenzie
12-28-2010, 4:22 PM

On your laser system motherboard is a memory simm, this is what i was suggesting to reseat or replace.

Colin Jenkins
12-28-2010, 5:11 PM
I got the SIMM out OK. Any idea how to determine what it is so I can replace it. Apparently Crucial.com carries componnets for ULS machines but they don't have records for one this old. I found this online but am not sure about the speed.

4MB, 70ns, 4MX8, non-parity, 8-chip

Mike Mackenzie
12-28-2010, 6:55 PM

30 pin 4meg or 16 meg will all work parity or non parity will all work the speed does not matter.

Richard Rumancik
12-29-2010, 11:28 PM
Mike, this is the same memory that was used in 486-vintage PCs, isn't it? If you can confirm this them perhaps Collin can find some old 486 memory sitting in a drawer that would work.

Mike Mackenzie
12-30-2010, 11:28 AM
Yes, This is the same memory used in older computers

Robert Walters
12-30-2010, 12:28 PM

Do you by chance have your laser in the garage or a warehouse?

If so, you might consider pre-heating it (power it on) for 30-40 minutes before running a job.

With the lower temperatures and high humidity in SoCal lately, there may be thermal expansion occurring on the laser's main board, control panel, and/or it's connectors.

Also as Mike recommended...
Grab a can of air and clean out any dust bunnies from the power supply and the rest of the electronics (power cord removed). Also check to make sure all cables/wiring connectors are seated correctly. If you haven't done so, remove the filters from the fans and GENTLY rinse under warm water and let air dry flat on paper towels, don't twist or wring them out.

Kay Bengtson
12-30-2010, 7:28 PM
I have mine in a garage and it does get chilly ( temps in the low 50s ) here on the central coast of California. I found that putting a heating rod, like those used to inhibit mildew in closets, inside the unit when it is not in use, keeps the belts and some of the components from getting too cold. Before I did this, I did notice that on startup, the first cuts were sometimes way out of place. Also, I heat the area up with an electric room heater for about an hour before turning on the electronics including the computer. Cold computers don't boot up well. Don't ask me how I know...