Night Vision Need help with PVS-4

[tbeasley]

Guys
My focus will shift after every shot. I was told about tighten the drag down. What on earth were they referring to?
I know the Diopoter is the hexagon looking knob and the objective ring is the bigger one on main tube for target clarity.

Question is can someone walk me through pretty please
If u like, please give a shout. 979-540-7279

Thanks..Tim

 

[cj7hawk]

Re: Need help with PVS-4


Is it the main focal ring moving or the diopter? Use some duct tape to lock it down and work out what is shifting.

Anyway, look for your PM - I'll send you some technical information.

Regards
David

 

[GBMaryland]

Re: Need help with PVS-4

The course focus (the big ring) is somewhat controlled by the condition of the large O-ring. So if that's not terribly warn, then it shouldn't shift.

The diopter adjustment is a little bit of a different story. They can move a little, especially of the eye cup is tight and doesn't swivel freely.

I've got a 3 inch lens on a TVS-5, and that eliminates the issue of the dioper moving... grin.

 

[yellowcarbon]

Re: Need help with PVS-4

Also, make sure it is properly assembled. I bought a PVS-4 off of Ebay that the owner said didn't focus 100% of the time. The rear half wasn't corrected screwed on and was causing focusing problems.

 

[GBMaryland]

Re: Need help with PVS-4

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: yellowcarbon</div><div class="ubbcode-body">Also, make sure it is properly assembled. I bought a PVS-4 off of Ebay that the owner said didn't focus 100% of the time. The rear half wasn't corrected screwed on and was causing focusing problems. </div></div>

That's a really good point: behind the course focus ring is a metal lock spacer that limits the travel of the course adjustment. If you loosen it, screw in the course adjustment all the way (gently), push the loosed lock ring forward, and then back out the adjustment until an object at 25m away comes into focus... You can then hold the lockring in place and tighten the lockring screw.

Thats the easiest way to do it...