Hello,

I've got a broken Simrad KN203FAB that I've been fixing.
It came to me without documentation, mostly disassembled, missing the front lens retainer ring, and with a broken power supply.


I've got the power supply sorted out.
I've made a replacement front ring.
I've built a jig to set the output lens focus and intend to give that a try soon.
(I'll be back with more pics and info on fixing it once I finish it)

I've scoured the internet for info, not found anything, and had a couple questions that I was hoping fellow owners/users might be able to help with:

1)  Does anyone have a pdf manual they could share?  If not, anyone have an extra paper manual?  (for sale or loan, I've got a scanner)  
(for any of the Simrads, I imagine they're all close enough)

2)  What do you do with the day scope when using the Simrad?
Parallax to infinity, leave the ocular adjustment at your regular day setting?  (I think this is how it's supposed to work, but I don't know, so I'm asking)

3)  I've gone through it a couple times, and had another guy with experience in these things look at it, but I've got this flat spring that came in the box of parts and can't figure out where it goes.  
At this point, I suspect it doesn't even go in the Simrad and was accidentally included.
Any ideas?  Recognize this spring from anywhere?


There's no spot for it against the tube, and the power contacts seem sufficiently spring loaded to keep it in place.

Thanks!

You are a brave man. Does the tube work? Can you take a pic of it for me?

As for use you zero it at 100yds with the day scope. And adjust for the offset which is about 1mil@ 100 i forget the exact number. (Zero it high at 100). Then its more or less on.

Thanks,
I'm tracking that for zeroing (but will have a question or experiment on that once this is usable).

I'll see if I can add more info and explain my day scope question a little better:
There's a lens in the output path from the intensifier tube to the day scope.  This lens is in a threaded housing and has maybe 1/2"-5/8" of adjustment range with a locking set screw to hold it in place.
I need to set the position/focus of this lens.

If I understand this thing correctly, this lens should be collimating the output image from the tube to approximate an "infinite" distance object for the day scope.
Now that I've thought this through again, I'm pretty confident this is the case.  I was asking about day scope parallax/focus settings because I think that if it's anything other than "set parallax to infinity (if adjustable) and leave your ocular alone", then it would tell me that something else is going on with the lens focus and that I'd need to change my plan for setting the lens position.

I believe the tube is good.  It was described to me as good
I've assembled and eyeballed through the thing, I could get a "sharp" image at about 50 yards, but I'll caveat that it's a pretty small output image to just eyeball.

I've briefly mounted it on a scope, the image was seriously out of focus.  I disassembled and reassembled a few times and had it at the point where the image was out of focus, but after a few seconds the image would sharpen (I think that was my eye compensating, kinda like those hidden image puzzle things).
Unfortunately, for that test I was looking at an overgrown treeline about 30 yards away (at 4.5x), so it was difficult to really tell what was going on or how good the tube is.

I'll definitely try to get some through tube pics next time I have it out.  If my lens adjustment plan is right, I might even have some photos that aren't blurry.

Email Ed Wilcox... he’s good people and will most likely be able to help/be an amazing resource.

https://wilcoxeng-res.com

[email protected]

Its a good idea, but last I talked to him, he had never worked on simrads. I think SPA is out of business, Aurora Tactical might have parts or an idea of folks you could talk to possibly.

I see. As I use it I use whatever parallax setting on the scope for the range I'm shooting (use 100yd setting for 100yd, etc), so the simrad is collimated at infinity "I think". Also, testing at lower power is probably best, it doesn't do great beyond about 8x (10x is ok).

Could you post pics of the tube, I've heard it has a fiber optic bit attached to it, but I've never seen a pic of it.

I attempted to set the focus Sat night.
It was out in the woods (tallish trees, but no leaves) with clear skies and no moon.
Also, it was way too cold, so I didn't get a lot of pics.

Here's the fixture:



After disassembling and reassembling a few times, I realized that the mirror/boresight assembly was only redirecting and inverting the image, so I didn't need it in place to focus the thing.
I made the fixture and a hollow spanner so that I could look through it while adjusting the lens.




I first set the focus with the Simrad set to 25m, looking at a set of rubbermade tubs positioned at 25m.
It turns out that's too close and you need to set focus at infinity (I suspected as much, but 25m was easier to work with).

I pointed the thing at the sky and adjusted using the stars.  I'm not sure I got it quite right.  
Unfortunately, I only had ~125 yards to work with for ground objects, but I had it where I could get a sharp image at 125 yards with the fixture and the spotting scope (12x).




When mounted on the rifle, the image is sharp to about 6x, then any higher magnification and the image gets blurry and unfocused (not focus-able).
When I turn the dayscope magnification, the focus through the Simrad appears to change as if I was turning the Simrad focus knob.
I'm not sure if something's up with the boresight assembly, alignment to the scope, or if I need to play with the focus more.
(I didn't fully assembly it with all the hardware, I'm just doing non-firing testing and assembling/disassembling).

I'm disappointed with the tube.  I compared it against an old filmed 3rd gen PVS-14, the PVS-14 image was much brighter and it saw in the woods a lot better.  (Magnification and FOV aside)
The Simrad needed additional IR illumination to pick up anything useful (the image with the tubs was with additional illumination, FWIW).  Given the comparative objective lens sizes, that seems wrong.
(the Simrad objective lens is dirty and I need to clean it inside and out, but I don't think it's that dirty)

I admittedly don't have a lot of experience with night vision or other devices to compare it against, but I'm starting to suspect it might be a 2nd gen tube (it was described as a 3rd).
I'm going to try calling ITT this week to see if they can get me any info on it.  Maybe it's just old, or I'm expecting too much (or maybe the pot on the power board is set wrong?).  Dunno


This is the best tube photo I've got right now (it's still assembled and I'm not in the mood to take it apart for better pics tonight)

How much does that weigh? It looks huge.

Simrads Ive seen/used have variable gain. Is it turned up all the way? Most of the ones in the US are omi4-5ish filmed based on the era they were built. And yeah, they stop looking great after about 8x in my experince, but usable to 10x mag.

Also as a point of historical curiosity, most European sniper optics in the 90's were typically in 6x range.

It is huge, but fairly light 2 ish lbs maybe? Plus it sits over the center of mass of your gun so its not bad like a huge clip on sitting on the end.

This one is variable gain, controlled as varying resistance to the pigtail coming out of the tube.  The power contacts are on the side of the tube.
I cranked it up pretty far,  it got lighter, but didn't see into the shadows any better if that makes sense.

For the Simrads you've used, did you need to refocus the Simrad when changing magnification on the dayscope?  I suspect it's a sign I dont have the output lens focus right.  Maybe I should retry the focusing with the dayscope instead of my spotter?


I need to look at image tube dimensions,  but I suspect this is a fairly normal tube with the exception of the variable gain pigtail.  I think I might be able to drop in a 3rd gen tube, maybe adapt a manual gain pvs-14 tube.  How does the manual gain function work on them, and are any recoil rated?

Its been a while since I used mine. I basically set parallax to what it should be, focus simrad. Double check parallax. And if need be refocus and re-check.

Is the tube inverting or non inverting?

I don't know.  Is there a way to check looking at the tube, or do I need to look at the optics path and sort that out?

It's an ITT F9811D tube.
I found this document:
https://www.asu-nvg.com/Documents%20and%20Settings/39/Site%20Documents/Product%20Spec%20Sheets/MX-10160_F9800_Int.pdf
That document claims the F9800 is an inverting MX-10160.  Based on the part numbers, I suspect that the F9811D is a variant of the F9800 and is probably inverting.
So maybe MX-10160 type tubes could be adapted into this housing?

I did get with ITT; apparently, it's an old Gen 3 tube, shipped September 2001.  
I'll attribute the poor low light performance to it being an older tube (hours and/or manufacture, I guess).
It's so old that they don't have any documentation, but they do know that they no longer make this style tube.

I adjusted the fixture and took it out again:


I took a different approach to focusing and had much better luck this time.  I'm thinking that the factory focus settings for the Simrad objective lenses are probably good, so I played with the output lens focus until I could adjust my dayscope from 4.5x to ~15x with the image quality (apparently) decreasing due to the magnification of the intensifier output rather than the loss of focus as magnification increased.  (to use a computer analogy, you can only magnify a 640x480 image so much before you're looking at pixels and not a real image)

Skies were clear, maybe 3/4 moon, same wooded area as last time.

Obviously, my cell phone pics don't help things.  The image looked a little better to my eye than these photos indicate.

This is a set of plastic tubs at 100 yards, 4.5x
(middle of the path, just under the thick vertical stadia, there's a tree right behind them)


10x


10x, +illumination


The black smudge on the bottom tub is a electrical tape "+", roughly 3" tall by 3" wide.
This is my first time dealing with a Simrad or any real CNVD, what kind of detail or resolution should I expect?
Should I be able to see the "+" clearly at 100 yards, or is a smudge about all I can expect?
(and what sort of difference should I expect between an 18 year old tube and a newer one, if I try to replace this tube?)
I'm trying to get a sense of if my focus job is good or needs more work, vs it being the image tube, vs performance being typical for this sort of thing.

Inverting means the image you see coming out of the tube is inverted and needs an optical path to flip it. Non inverting have a fiber optic built into the tube that does it.

Your 640x320 analogy is spot on, most CNVD's use a demagnifier to let you use magnified optics with the tube. The old Simrads as I've mentioned start looking not great after about 8x due to this.

As for the 18 year old thing. Resolution wise those tubes are at least 64lp/mm or better modern stuff isn't gonna get you much there, gain wise, yeah modern stuff is probably better on average in really dark situations, but assuming its near Omni5 specs the SN is probably in the mid20's and maybe higher, alot depends on how how "hand selected" the tubes are. Also, most CNVD's aren't gonna do great in the woods.

Your pics don't look great relative to what I'm used to seeing, but I don't know how much of that is phone pic vs the real image you see. Not sure on your plus, but I can see a 1" dot pretty clearly with the simrad at 100 when I zero.

It sounds like I need to adjust the focus a little more, I definitely wasn't seeing that kind of resolution/clarity.
To my eye, the "+" was just a smudge (a nicer smudge than my phone pic, but still a smudge).

Pretty sure it's noninverting.

Meah thats my assumption too It does kinda look a bit like MX10130 with variable gain and different power contacts, Its been a while since I looked at the patent which has the optical path diagram. Years ago I heard from folks that the tube had some fancy fiber optic coupler on it that was supposed to increase/help with resolution maybe on the input side? Maybe the OP's tube is missing it, or those folks could well be wrong on that point.

Yeah, at 100 things are pretty clear focus-able. I'd try to make sure you have good illumination of your target area out in the open on a moonlit night as an example, no point making it harder than it already is. You might have to futz with the simrad focus, and the scope focus/parallax though. And I'd try it at lower mag like 6x first. Honestly I'm impressed with the fact you've pulled it apart and put it back together and that you've gotten it as good as you have without factory manuals and gear/test benches.

I haven't had a chance to work on the focus more, but I did open it up to clean the lenses and double check that I had the tube seated correctly.

Tube pics:

Cool. Thanks.

Glad to see this unit up and going again.  I used to be it’s owner oddly enough when the power supply ate shit.

What was wrong with the PSU out of curiosity?