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  1. #1
    Join Date
    Mar 2017
    Posts
    2

    G Weike LG900N Laser won't fire

    Hi all, I've been reading the forums here for a while and they have been extremely helpful but I finally have run into a problem that I can't seem to solve. I've had my LG900N for a year, and this morning after making a few cuts normally the laser just stopped firing. The laser tube does not glow at all when I try to test fire it. I tried the following steps so far:


    • Took the magnet out of the top door and placed it directly on the hall-effect safety sensor. No luck.
    • Followed the instructions in this video to test the PSU: https://www.youtube.com/watch?v=dz4ln4_vT3g
      This involved removing the anode and cathode connectors from the laser, putting a resistor in between them, removing the data-line from the PSU and replacing it with a test plug that has the 5th and 6th pins wired directly to each other. When I pressed the test button the red led lights up and the ammeter read 24ma which is what the laser normally runs at.
    • Luckily I have a brand new spare tube, so I removed the tube and installed the spare. Turned everything on again and still nothing.


    It seems unlikely that both tubes are bad, and the power supply was giving the right amount of power. Is it possible there is something wrong with the safety switch? Is there a way to override that to test? Any advice for how to trouble shoot would be greatly appreciated.

    Thank you!
    --Chris

  2. #2

    Re: G Weike LG900N Laser won't fire

    Quote Originally Posted by dasbachc View Post
    Hi all, I've been reading the forums here for a while and they have been extremely helpful but I finally have run into a problem that I can't seem to solve. I've had my LG900N for a year, and this morning after making a few cuts normally the laser just stopped firing. The laser tube does not glow at all when I try to test fire it. I tried the following steps so far:


    • Took the magnet out of the top door and placed it directly on the hall-effect safety sensor. No luck.
    • Followed the instructions in this video to test the PSU: https://www.youtube.com/watch?v=dz4ln4_vT3g
      This involved removing the anode and cathode connectors from the laser, putting a resistor in between them, removing the data-line from the PSU and replacing it with a test plug that has the 5th and 6th pins wired directly to each other. When I pressed the test button the red led lights up and the ammeter read 24ma which is what the laser normally runs at.
    • Luckily I have a brand new spare tube, so I removed the tube and installed the spare. Turned everything on again and still nothing.


    It seems unlikely that both tubes are bad, and the power supply was giving the right amount of power. Is it possible there is something wrong with the safety switch? Is there a way to override that to test? Any advice for how to trouble shoot would be greatly appreciated.

    Thank you!
    --Chris
    Hi Chirs,

    if you had test as the vdeo we send and if all tiube and power supply ok , no problem,
    ,then please check the wires ,see if any wire not connect well. pelase check all wires form power uspply and tube, make sure lal wires connect well.

    ok ,any quesitons please conatct me directly.

    QUIVEN form gwieke laser
    [email protected]
    skype:wkquiven

  3. #3
    Join Date
    Mar 2017
    Posts
    2

    Re: G Weike LG900N Laser won't fire

    Just to follow up on this, my issue turned out to be the power supply. Swapping it out with a new one from lightobject.com did the trick. When I pulled out the old PSU, one of the thick wires was melted through so it must have shorted out at some point. It's odd that the ammeter was still reading correctly when doing the large resistor test, perhaps the short only affected circuitry which is active during actual operation and not the test.

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