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Thread: Lexel 95 HELP!

  1. #1
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    Default Lexel 95 HELP!

    I have a lexel 95 laser. It had been working in the past but has been sitting for awhile. It only has about 400 hours on it. I thought that if I ran it for awhile it would lower the pressure inside the tube and it would start working again. However, I tried it in all current positions but the laser will only turn on if it is in the light control position. No matter what the settings are the laser power is always 0 with the light control all the way up. And the purple beam is coming out of the laser. As soon as I switch to current control it shuts off the laser immediately. And if I try to turn the laser on when current control is on it lights up for less than a second and turns off. It's the same time every time. I was wondering if anyone could tell me why this happens and how I can go about fixing it. But I only ever get a purple beam from the laser.

    I appreciate any help or suggestions.

  2. #2
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    Can you provide a picture of what the output looks like in light control mode?

  3. #3
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    Quote Originally Posted by turbohead View Post
    Can you provide a picture of what the output looks like in light control mode?

    Click image for larger version. 

Name:	IMG_3784.JPG 
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Size:	1.71 MB 
ID:	46277 Is this what you mean? Or do you want to see the laser that is coming from the machine?

  4. #4
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    Quote Originally Posted by blanders View Post
    ...but the laser will only turn on if it is in the light control position. No matter what the settings are the laser power is always 0 with the light control all the way up. And the purple beam is coming out of the laser.
    Can you post a picture of what you are describing in words.

  5. #5
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    Quote Originally Posted by turbohead View Post
    Can you post a picture of what you are describing in words.

    I have posted these two videos. I hope this helps! I appreciate any feedback!

    https://www.youtube.com/watch?v=rhQEkR6PdgI
    https://www.youtube.com/watch?v=eLGj...ature=youtu.be

  6. #6
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    At a minimum, the mirrors are likely out of alignment. The front output coupler is rather difficult to reach however the rear likely has very easy to access knobs for alignment. It's very easy for those to get bumped slightly. The purple glow is plasma, if you're brave enough, you can turn the two knobs on the rear of the laser to see if you can get it back into alignment. Just understand that if by chance it's the front output coupler that's out of alignment then adjusting the rear high reflector is just going to make matters worse. The issue with running the laser in current mode might just be a problem with the current control board within the power supply. It should have a current control board and a light control board. Sounds like one is working and the other isn't.

    I posted a video a while back on alignment, perhaps it'll help: https://www.youtube.com/watch?v=U8yLS4K8nM4

    Where are you located?

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    Quote Originally Posted by DZ View Post
    At a minimum, the mirrors are likely out of alignment. The front output coupler is rather difficult to reach however the rear likely has very easy to access knobs for alignment. It's very easy for those to get bumped slightly. The purple glow is plasma, if you're brave enough, you can turn the two knobs on the rear of the laser to see if you can get it back into alignment. Just understand that if by chance it's the front output coupler that's out of alignment then adjusting the rear high reflector is just going to make matters worse. The issue with running the laser in current mode might just be a problem with the current control board within the power supply. It should have a current control board and a light control board. Sounds like one is working and the other isn't.

    I posted a video a while back on alignment, perhaps it'll help: https://www.youtube.com/watch?v=U8yLS4K8nM4

    Where are you located?

    I am located in Cincinnati, OH. I have tried moving the two nobs on the back to try to realign the laser but it did not work, so I assume it is the mirrors in the front. From your video I will have to realign both then? Also, would the mirrors being out of alignment cause the Laser Power meter to be 0 when on light control? Also, do you have any suggestions on what to do with it clicking off automatically when I turn it to current control. Also, will it work to realign the lasers if I am in light control? Will the flash still occur?

    Thank you so much for your help, I really appreciate it.

  8. #8
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    Did you bump the laser since the last you operated the laser?

    Typically, you should be able to get a beam by walking the rear mirrors. Front mirror alignment is usually done to peak the output power unless they were way out of alignment in the past.

    Scratch aligning the mirror takes experience and a lot of patience although the video by DZ is excellent.

    I would not rule out the possibility of some fault in the power supply. However, if the power supply was working before and you did not subject the supply to some adverse condition, the cause is pointing to the tube.

    Was the tube hard to start in the past?

    Do you have a meter to check the voltage on the filament?

  9. #9
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    I am wondering, did you ever get an output beam in the past such as this:

    https://www.youtube.com/watch?v=LE4wPcW2sq4

    What is your source of three-phase power?

    Quote Originally Posted by blanders View Post
    Also, would the mirrors being out of alignment cause the Laser Power meter to be 0 when on light control?
    The power meter will only register if there is actual coherent laser output. As DZ stated, the purple flash is just plasma glow in the tube.

    Quote Originally Posted by blanders View Post
    Also, do you have any suggestions on what to do with it clicking off automatically when I turn it to current control
    I am not familiar with the detailed operation of the Lexel 95 power supply. I am speculating that the power supply is automatically "clicking off" due to an over current condition. In other words, the plasma strike is occurring, but because of either high pressure in the tube, or a fault in the power supply, the circuit is engaging some type of protection and turning off the power. There are people on this forum who know much more of the technical details of the Lexel 95 power supply. With patience they may provide some guidance.

    Quote Originally Posted by blanders View Post
    Also, will it work to realign the lasers if I am in light control? Will the flash still occur?
    It appears you are able to get a sustained plasma discharge (purple glow) in light control mode. If this is the case, you want to "walk the rear mirrors" (small adjustment) until you get an output beam.

  10. #10
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    I AM familiar with the internal workings of the Lexel PSU.

    I've made a Powerpoint on troubleshooting Lexel current cards. You have a defective current card feedback section. It starts in light because the low voltage power supplies on the current card are working and powering the light card. I'm at work, I'll post the power point when I get home. Probably need to replace one of four socketed parts or a defective switch. Its easy.

    Right now because you've started in light mode but have no lasing, the PSU is running the tube at full current NEAR OR ABOVE the Emergency Overcurrent trip point. This is hard on the tube as the factory sets the upper light limit 4 amps above the normal upper current limit. I'd fix the CC card before going further or before setting up for lasing.

    Did you set the taps on the three phase transformer per the tap chart in the manual?

    Steve
    Last edited by mixedgas; 02-09-2015 at 10:36.
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