Night Vision Dropped my 14 and now it won't focus

earthquake

Area Man
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Minuteman
  • Jul 30, 2009
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    I bought a used PVS-14 off a guy here earlier this year. It's a basic Gen-3 model, green, manual focus etc. It recently fell off a low shelf in my safe onto the safe's floor, or about a 12" - 18" drop. Now it won't focus on anything but from arm's length to about 6' out. I figured these things were supposed to be Marine-proof!

    Any idea if this is something I can fix on my own or how much it'll cost to repair? What the f'ck "broke loose" inside from such a short fall as to render it almost useless?

    Thanks.
     
    You can fix this yourself most likely. The tube retaining ring likely popped out. Or the inifinity focus ring moved.

    Look at the inf ring first - its on the bottom right above the rear lens, and looks like this:

    1634912951038.png

    Screw this ring by hand towards the center of the unit and see if that fixes your stuff.

    Here is a quick guide to the rest of the process.


    Get a can of office supply air duster - remove the rear lens by unscrewing it at the large lockring set thats down below. Most 14's are just hand builds and aren't locked in place, nor is it really necessary.

    This will expose the top of the tube - look to see if the lockring moved.

    Its also possible that your housing is stripped, or your front lens. Disassembly is pretty easy with these to figure it out, and repair isn't too challenging.

    Use the air duster to get shit off your lenses and re-assemble/test.

    If you live in a humid environment you can use this to get most of the oxygen/moisture out of the unit. Not as good as a real purge, but still decent. Unscrew the purge screw and jam the tube of this guy in there, spray it pretty good.

     
    yeah the front/bottom ring is the one that probably got you. it moved when it hit the carpet and prevents you from focusing any further. just screw it in as far as it goes and you should be fine.

    Also , you should refocus the back end. You do that by trying to see specs and dirt and shit on the back lens clearly, then focus the front. Most systems have a hexagonal grid on the back that you can see if you have great eyesight.
     
    if it will only focus close then chances are the tube has moved back a little , as someone said , because the front lens needs to be close to the tube for far focus , make sure the front lens is turned out before you tighten the tube lock ling as if front lens too far back it can stop the tube seating properly (front lock ring normally prevents front lens fron moving back to hit tube)
     
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    Update...

    Killswitch got me squared away. Was having trouble with it at the East Coast NV shoot at TVP last week. It worked fine, but after setting it down now and again and putting it back on, it would be very blurry again. Then I could feel something chunky inside moving back and forth.

    Opened it up and found this:

    IMG_20211111_141630394adc.jpg


    Lock ring was on the eyepiece(?) lens and the plastic thing was cocked.

    IMG_20211111_141558571.jpg


    Pushed it back in place, removed the lock ring from the lens and screwed it down onto the image intensifier. However, there are barely any threads exposed for that lock ring to screw onto! Maybe 1 - 1 1/2 threads! If it comes out again, can I ditch that plastic thing? It would give me more threads for the lock ring to engage.
     
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    Reactions: MarshallDodge
    Damn... messed up the quote deal. Senor moment.... but not quite a senor.

    If you mean the lightpipe for the "plastic thing"- no you want to keep that.
     
    I meant that flat plastic ring/washer looking thing that's cockeyed in the photo.

    thats the light pipe that lets you know when the onboard ir is on. i would leave that in there and do as mentioned above. you likely have something keeping the tube from sitting down into the housing as afar as it needs to. back your objective lens out all the way and see what that does.
     
    Glancing back at the pics, I don't see a tube retaining ring or did you remove that already?

    Kind of confusing to look at for the first time but it's like the others stated-
    1. The tube should sit lower. You can extend your front lens a bit to help this- then you should see the threads above where the tube sits.
    2. The lightpipe goes on top of the tube, needs to be set in the right place.
    3. The tube retaining ring screws down on top of this to hold everything in place.

    Then finally you put your eyepiece lens on.

    If your unit was smacked around that bad, I would open the whole thing up being as your right there anyway- check to make sure the tube still fits in the little "key" area of the housing that makes electrical contact. Might want to check your gain control pins and ribbon also.

    UNV has a good video on youtube on PVS14 DIY building, it's worth a watch.

    Finally, clean everything really well before re-assembling. Good luck!
     
    I see said the blind man LOL. Missed that pic.

    How hard does a 14 have to drop to cause this? Now I'm interested in finding out!
     
    I see said the blind man LOL. Missed that pic.

    How hard does a 14 have to drop to cause this? Now I'm interested in finding out!

    i feel like there is crack or failure in this housing or the internal threads arent to spec. something is amiss. ive beat my 14's (inadvertently) like red headed step kids and never had an issue.