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View Full Version : ULS doesn't stop firing problem - help neaded



Benedict Roussos
03-06-2009, 10:09 AM
Dear friends , good evening from Greece.
I have a problem with my ULS V460 and the greek representative of ULS didnt find the answer. Untill next monday I cant stand waiting so I 'm searching for extra help. When I turn on the laser, the beam fires before I send any file. It doesn't stop firing at all. Raster or vector it fires continuasly. I have reset the dipswitches again, I took out the laser bottle, I checked the cpu for dust or something else but nothing! I'm waiting for a spare laser bottle next week to test if the problem is there. Any idea anyone ??

Mike Mackenzie
03-06-2009, 12:38 PM
Benedict,

What are the dip switches set to on the laser tube? Also look in the laser system and check to see what the firmware version is. Is this a UL Tube or a ULM tube? Give me the system serial number and laser tube S/N and I can check some things for you.

Dan Hintz
03-06-2009, 1:54 PM
Mike, what are you thinking, a too-high tickle voltage setting?


I'm not sure what kind of access you have to the wiring, but I would check the enable line with a voltmeter... a solid 5V would mean the laser is probably okay and someone else is telling it to fire. If it's still around 0V, it's internal to the cartridge.

Benedict Roussos
03-07-2009, 3:17 AM
Ok. I'm back with a lot of details. First of all ULS V460 50 Watt with air assist S/N 10390 manufactured 4/2004.

Tube S/N 11,240C and tube dip switch settings : 1 OFF, 2 ON, 3 OFF, 4 OFF, 5 ON, 6 ON, 7 ON, 8 ON.
I use the machine every single day except Sundays so the tube is (at least was till yesterday) in excellent shape

although it is working for almost five years for an average of four hours per day.
Let me now describe the problem in a more detailed manner:

Let's say that I want to cut out 6 circles 1" diameter from acrylic sheet (plexiglass)
I switch on the ULS after leaving it to rest over night and everything seems ok.
I set X-Y-Z and everything still seems ok.
I make the drawing in CorelDraw X3 and send it to the ULS using the Win XP Driver ver 1.07M 100% power, 4% Speed,

1000 ppi
I press START. The ULS starts cutting
It cuts out the fisrt three circles correctly, but when it begins to move to the start point of the fourth circle,

the laser beam isn't shut off like when it had moved from the first to the second and then to the third. The result

is an engraved straight line from the end point of the third circle to the start point of the fourth circle. It

then cuts out the fourth circle, it engraves a straight line from the end point of the fourth circle to the start

point of the fifth circle and so on until it finishes cutting the drawing I sent from corel and then it moves to

the top right of the table as usually, only with the beam still on and this way engraving a straight line from the

end point of the whole drawing to the top right point of the table. The ULS beeps to indicate the end of the job

but the laser beam is still ON without moving. The beam shuts down only if I open the hood but when I close it

fires egain and stays on till I power off the ULS using the power shitch. If I power it up again the beam fires

again without moving and so on till next morning.
The same thing happens when I try to engrave raster. The beam fires at the points it should but it doesn't stop at

the "gaps" so the result is an all black square.
From my experience I think that the tube instead of almost stopping the laser beam as it should, it keeps firing at

approximatelly 20% of the max power the driver told the ULS to use, CONTINUOUSLY. NOT PULSED!!!!
I have heard about the tickle thing and I had experienced problems in the past with particular very glossy

plastics. That is, while negraving, because the beams dosn't shut off completely when the head stops, I notice some

marks at the right end of the engraving and specifically at the point the head, while moving to the right, stops

before moving to the left. I got around that problem simply by placing a pieace of paper at that point.
The qualified person of the ULS representative in Greece, drived me, by phone, through the diagnostics - alignment

menu of the ULS. In this menu I used the following settings : power 5%, KHz 3, beam 1. I moved the head over a

piece of very thick (0.12") paper and by using the X-Y button I fired the beam. While the beam was on and the ULS

was beeping, I could see the paper burning, when I pressed the X-Y button again to stop the beam, it kept firing

only at less power, and if at that time I tried to move the head it engraved the paper beneath.
Any way the beam is firing all the time and stops completelly only when I open the hood. From my experience in

electronics, the problem is in the tube, not the cpu neither the power unit. Speciffically in the pcb board inside

the tube.
Besides any suggestions that would be appreciated, does anybody know if this (these) pcbs are replacable, and

second, when the tube reaches the end of it's life, in what manner it behaves?

Thanks in advace to all who will read this post and especially to those who will help.

Mike Mackenzie
03-09-2009, 12:32 PM
Benedict,

Your description of the problem is the RF board in the laser tube. You will have to replace the laser tube.

Your life span of the tube falls right into the time line of expectancy. IE we have a very good estimation of the laser tubes operational life and 3-5 years is common. Although it does appear that this is electronics due to the age of the laser tube you should just get the exchange and move forward. ULS will not just replace the RF board because they are factory tuned.

I would contact your local representative and work out the details in getting a replacement.

Dan Hintz
03-09-2009, 12:38 PM
Mike,

A while back someone mentioned ULS sent them the procedure for tuning a new RF board. I believe I have the equipment, any chance you have the procedure? I want to be prepared when mine goes south.

Benedict Roussos
03-09-2009, 1:30 PM
Thank you very much Mike and Dan, the greek representative informed us ,this morning, about the problem we have and we have already ordered a new tube to replace it.

Mike Mackenzie
03-09-2009, 1:47 PM
Dan,

My guess is that person who asked for the procedure was using an OEM tube. We do not have the procedure also with the new ULR laser tubes they would be different. (This is the type of tube you have). Benedict has the UL tube.

I believe they supply these to the OEM market because most of the people who are using these tubes are automating them into assembly lines and for them to replace a tube when it is a known problem coming from the RF board it is easier to deal with. Most if not all OEM customers have the equipment to do this type of work.

You could ask the MFG if they would supply you the tuning spec's all they can say is no.

IMHO It would be cheaper and easier to just exchange the tube once it is needed because if the RF does go bad and you could replace it for a cost and then spend the time to tune it and then the gas goes out in six months, or an internal optic fails you would need to do an exchange anyway.

One thing ULS does is to completely re build the laser tubes, The electronics are Updated , The optics are replaced with in the tube, The tubes are cleaned and refilled with the gasses and all internal alignment is preformed. Basically you are getting a complete "new" rebuilt laser tube once the exchange is needed.

Regarding your first post I was wondering if the system and the laser tube were counteracting each other. On some systems the tickle signal was set on the system and on others they were set on the tube. If Benedict was sent a UL tube and he had the ULM then there could have been a problem with this setting the signal on both the tube and the system.

However with his last post the RF is definitely the issue.

Benedict Roussos
03-20-2009, 12:33 PM
laser tube reloadead!!
V460 is cutting again.
A big thanks to Universal Laser for their fast service even if we were to the other end of of atlantic. (6 work days from our order)