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Dissecting the TSN-82* (1 Viewer)

pinussen

pinussen

Well-known member
Found a "broken" TSN-823 on ebay, sticky and stuff on the lenses etc. Snapped it up for £127 :eek!:

Worst case I could use it to fix my 824:
http://www.birdforum.net/showthread.php?t=213304

It arrived today and ofcourse I ripped it apart to try and fix it. So, why not document it a bit to help anyone else trying the same. Btw, anyone knows how to make inline images??

The scope:
4e6c32d0-b947-d48e.jpg


First separation, the scope unscrews at the middle:
4e6c32d0-b96a-12cf.jpg


Removed the back plate. unscrew the sight and two hex screw inside (2.5 mm):
4e6c32d0-b998-85c3.jpg


Removing the optical stuff except the focuser. Undo three hex screws and the two small ones that holds the focuser. Slide out the whole plane with mirrors and lenses. Make sure you don't loose the packing and the little ball at the end of the focus screw.
4e6c32d0-b9d2-9391.jpg


First additional problem detected. The focuser slides on the pole and only has two flimsy plastic pieces guiding it, one was broken making the focuser rock slightly back and forth when focusing. The small piece glued back on:
4e6c32d0-ba01-6ac7.jpg


Glued a piece of polycarbonate to stiffen it a little:
4e6c32d0-ba31-56cc.jpg


Remaining problem, smudge and stuff on the main lens, or is it two lenses up front? Haven't figured out how to take this apart, anyone knows?
4e6c32d0-ba61-f38f.jpg


Which part went where now?? B :)
4e6c32d0-ba87-05d2.jpg


//Björn
 
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Why not, it was "only" £127 :)

If it could be fixed I would have a great "previous version" top of the line scope extra, if not I could use the parts to fix my 824. Spare parts for these are for some reason very hard to find, so if I can make it work I have saved a really nice scope :)

//Björn
 
You do realize you can get parts for the 823 so it can be repaired by Kowa. It's just the 824 you can't get parts for.

Anyway the front lens should plop out by unscrewing the metal discs holding it in. I think there may be a special tool that goes into the two slots opposite each other, I used a pair of small nose pliers to do it on an old Optolyth. Mind the lens though any mishaps and you could scratch it etc. I cut out a piece of card to protect it when I did it on my Optolyth.

Might be worth marking the lens position relative to the body before you take it out to facilatate assembly or possibly alignement.
 
Yep, some parts are available but I think just sending it off to the repairers for a cleaning cost about £100. And then you need parts on top of that if they are available. Now I have a nice "back part" that I can mate with the 824 front, i.e if I can't get this front and the prism on the 824 fixed. The technology in it is not really advanced, I guess it's just a matter of the optics being good and expensive. So you have to be careful with the optics.

I thought the metal rings would free the lens but I can't get them to move, the outermost has a dent in it, making it hard to move probably. I guess more power is needed and maybe a better tool, tried a saw blade now :)

btw, forgot to mention, it looks like someone has been in this one already. The last 45 degree prism was loose since someone had attached the spring steel thingies that keeps it fastened, upside down.. And I wonder how the front lens can be smudged on the inside?

It's a gamble to try and fix stuff but you always learn something and can save some money :) Worst case you loose the money and your pride hehe

//Björn
 
Now you know how it comes apart you should be able to fix in place the 824 prism.

It sounds like you need a bit more leverage to get those rings free. A drop of WD40 might help as well. You might damage the threads if there is a dent on the outer ring and try and unscrew it.
 
Yep, I'm in a good position :) If I can only get the 824 open with all the silicon in the thread. The ring might be available as a spare if needed, worst case I have to learn how to make threads on my lathe...

Just tested it on some street lights outside and i looks good with the 20x EP, I don't notice the smudging on the lens even though it's quite severe.

This is a great way to spend some money :) Another of my hobbies (I have too many) is model engineering so this is pure fun for me :)

//Björn
 
dipped said:
You do realize you can get parts for the 823 so it can be repaired by Kowa. It's just the 824 you can't get parts for.
Click to expand...

I truly did not know that. :-C
And mine's not even the M version! |8.|

I guess I should probably stuff some cotton wool or something in between the scope and the SOC!
 
Bjorn!..I saw that scope!..and thought of You since it was coming for auction the day we were talking about the Kowa(or about that day)....I was tempting to buy it myself but totally forgot to check the auction later or to tell You about It..amazing to see that You bought It!..The scope looked good ,How bad is the smudge?..Is it caused by coatings damage?.It was a great buy,of course...but for 100 or even 200 more it should be worth to send it to Kowa,if the lens is Ok and get the unit refurbished to the extent that is possible..I think...Well ,Your call anyway...
enjoy!


Hey!..Im back after looking at your pictures....well...the smudge is not too bad..is out of the way for the most part...It seems to me that could be separation of the elements here...like the cement,if the elements are cemented separated somehow...so the smudge is not inside but between the elements...Do you think this could be the case?...
I would ask Kowa,including Kowa USA,if the lens coatings can be redone...only for curiosity..maybe they can put some last generation multicoatings on that fluorite!!!!!!!!!!!!!
 
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Better pic maybe, hard to photograph the lens.

4e6c32d0-22a0-4458.jpg


Most of the smudge is along the edge. However there is also something that looks like frost or fog, fungus? Only seen when the light reflects on it. There also is something that could be a crack. It also looks like a liquid so I don't know :) It's on the same place as the dent though.

Will try to find a pic on how the elements are placed in the front, maybe in some Kowa promo material..

Hehe, yea didn't want to mention this scope when we talked in case you would take it :)

//Björn
 
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Tonights progress:

I couldn't get the outer ring to move at all, probably due to the dent. Had to destroy it to get it out... The lower ring could be removed quite easily but taking a piece of steel plate that fit the notches and turning. Below were a steel ring and below that a big o-ring.

The outer lens looks like it's free but I can't get it to come out. It only moves a few millimeters out before getting caught on the threads. Can't see a way that the threads can be removed. Otoh the sun cover has to be removable somehow... more investigation later on. Maybe the tube is slightly oval from the dent.

Interresting to see small differances between the 824 (early 800 according to serial) and the 823 (late 8000 serial), upgrades in the construction I guess.

//Björn
 
try to keep a reference to optical alignement by marking the lenses,maybe with a small sticker ,and set a reference in the tube,so You know exactly what the orientation of the lens is ..In case the optical center of the lenses is not the physical center of the lens cell.

If I decide that I have to destroy or crush through something, in these reconstruction processes ,I usually take a break,and rest for a couple of days before attempting to do so..

The feverish anticipation of success usually means failure,at least In my case,for I can overlook simple ,basic steps and precipitate into disaster or at least loose that bright vein of genius clarity..So I reccomend ,when things are moving,let them rest for a sec

A pressure tool can work very well to undo rings,..a rubber end,maybe from a crutch or a chair leg,can give lots of grip power and is safer if it slips against the lens than a steel tip.
 
I hear you, trying to take it easy :) I couldn't get the lenses to move so I asked the guy doing the Kowa repairs in Sweden and he advised not to try to get them out like that, too easy to chip the flourite lens.

Since the smudge seems to be on the back of the fl lens (the inner one apparently), not between the two lens elements it should be possible to clean "from the back", problem is that the tube is so long.. However, got a tip that the black metal part can be unscrewed from the composite tube so you can reach the back of the lenses. Tried it but I guess more leverage is needed.

He does not recommend to do this job on you own though since the inner lens is so sensitive. The outer ring might be available as a spare part.

Now, trying to put the ring back on, difficult with such large diameter to get the threads right.
 
Any updates in the reconstruction process of you 823?..im very curious about the outcome!

happy new year


Manuel
 
Hi,

haven't really made any progress, life got inbetween :)

Wasn't able to unscrew the outer metal part from the plastic tube, need to try and recruit some strong hands to help me.. I'll report back once I get some progress.

Happy new year!

//Björn
 
I would like to take a look at the attachemnts in this thread,but cant do it through tapatalk..any idea about how to proceed i order to see the images...?..i can use the info..
Thanks
 
The pictures seems to be gone from the tapatalk server. And I can't find any backups of the photos either. Sorry :(

//Björn
 
Well..I received my 823 today..paid a few pounds less than Bjorn,so i feel lucky..My unit has a cracked endp plate,and the prisms were out of place..I opened the prism box following The instructions in this thread and what i remembered of the pictures,and it made it easier,because i knew where to start...starting with the 2.5mm long neck hex wrench!..I was quite lucky because not a single piece had broken,nkt even the flimpsy guides of the focussing prism,so it was just a matter of repositioning the prism that has fallen from its saddle and all the optics are nowINTACT!..Sweet!..I have contacted kowa about replacing the broken part ,cleaning and repurging,but havent heard from them yet..unfortunately Spain only technical repair service for kowa closed last year.But i can mend the cracks and the scope is gonna befully functional until i get it serviced.I didnt take pictures of the process,because I did the whole "dissection" in the heat of the moment,but i will try to document the re-assembly with pictures to keep the thread illustrated.
 
I fixed the broken back plate and put the scope back together,..but i didn't take the pictures that i was planning to post... I might have to open the scope again because the 45° prism is a bit loose and rattles ..It is well anchored and there is no way to tighten more the screws that hold it in place,but i can put a touch of silicon or epoxy in the base to make it fit more firmly..If I decide to do this,I will do post the pictures...It is almost shocking how simple and low tech the system really is..and yet is very well crafted ,the prisms are large,and super well polished,and you can see some fine pencil markings to name the position of the prisms ,that suggest that the scope was carefully assambled ....The crack in the body allowed me to see the minimal density of the policarbonate body..it is almost foam!!!..very low density plastic in this original 82 series,.maybe too light for such a large scope,no wonder the series was changed to the M reinforced models....As you can imagine in such porous material ,Loctite adhesive did glue the crack with a vicious bite, I would say that structurally is as sound as new. It is amazing how well corrected the scope remains after all the ordeal .I guess the simple porro prism and Fluorite Doublet dont leave much room for misaligment. It took 300x with a lot of response in the cooler ,contrasty East view of the late afternoon...
 
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