taking apart a Nikon ED50 (fungus inside) (1 Viewer)

[temmie]

Hi all,
contrary to what some may think when reading the title, I haven't taken the scope apart (yet), but I'm planning to do so.
After 14 years of duty, the fungus has decided to grow just a bit too hard, and has now covered almost 100% of one internal lens surface.

The problem is that this lens seems to be somewhere at the eyepiece side, but under at least one other lens that is 'open' to the air, at the eyepiece side. So it's somewhere below the first air/glass surface underneath the eyepiece.

I know for starters I can remove the objective lens as the black part is threaded and easy to unscrew.
Below, I see a (I think) hex. bolt of around 2mms, but it's recessed a lot (and I will struggle to remove that bolt). I think the bolt holts the 2 main parts of the telescope body together, but I fear a bit for the focussing mechanism and any other damage I could do when trying to separate the parts.
At the eyepiece side (much closer to the fungus), there are 2 small indentations, seemingly made for a special lens tool. I have tried to put 2 ends of sharp pliers in their and twist, but it didn't open (and I scratched the inside a bit, luckily no lenses).

Does someone have some advice...? Or a (schematic) drawing of lenses in this scope body?
I consider the telescope as a write-off, but it would be fun to be able to clean it and use it for another 14-15 years

 

[Hermann]

After 14 years of duty, the fungus has decided to grow just a bit too hard, and has now covered almost 100% of one internal lens surface.

Interesting. That's the first case of fungus in the ED50 I heard of. The question is of course where the fungus entered the scope.

The problem is that this lens seems to be somewhere at the eyepiece side, but under at least one other lens that is 'open' to the air, at the eyepiece side. So it's somewhere below the first air/glass surface underneath the eyepiece.

Isn't that just a plain glass sealing the body when you switch eyepieces? I seem to remember there's no further lens below that glass, just the prism block.

Does someone have some advice...? Or a (schematic) drawing of lenses in this scope body?

I think there was a drawing of both the angled and the straight ED50 way back on this forum. I think it was in a discussion of what prism types Nikon used in the ED50.

I consider the telescope as a write-off, but it would be fun to be able to clean it and use it for another 14-15 years

Why not? It's a pretty good scope, even today. I even got a spare one in case something happens to my ED50.

Hermann

 

[henry link]

Since the photos are out of focus it's hard to know for sure what we are seeing, but this might not be fungus. Another source of possible deterioration is the silvering applied to one surface of the semi-pentaprism, which is located behind the Porro prism at the back of the body.

If you can make a photo that brings the plane of the deteriorated surface into good focus it should easier to tell if this is fungus or something else.

Henry

 

[temmie]

Thank you gentlemen, I will make better photos tonight (photos above were take with my phone, but I have better equipment available).

Meanwhile, after Hermann's reply I searched a bit, and found this: Nikon Fieldscope ED50 Separates

Probably, what I see, when looking through the objective side, is an image after it has gone through the prisms (so I shouldn't try to unscrew the hex. bolt...?
But then again I wonder how the hex bolts (there seem to be 3 of those) can be reached...?

@ Henry: I initially thought it was fungus as it only covered approx. 20-30% of the view (seen from the objective side, no visible quality loss from the eyepiece side) for some time (let's say the last 2 years). Only recently it started to 'grow' faster. But ofcourse that could be more rapid deterioration as well.

 

[Markbro]

Hi all,
contrary to what some may think when reading the title, I haven't taken the scope apart (yet), but I'm planning to do so.
After 14 years of duty, the fungus has decided to grow just a bit too hard, and has now covered almost 100% of one internal lens surface.

The problem is that this lens seems to be somewhere at the eyepiece side, but under at least one other lens that is 'open' to the air, at the eyepiece side. So it's somewhere below the first air/glass surface underneath the eyepiece.

I know for starters I can remove the objective lens as the black part is threaded and easy to unscrew.
Below, I see a (I think) hex. bolt of around 2mms, but it's recessed a lot (and I will struggle to remove that bolt). I think the bolt holts the 2 main parts of the telescope body together, but I fear a bit for the focussing mechanism and any other damage I could do when trying to separate the parts.
At the eyepiece side (much closer to the fungus), there are 2 small indentations, seemingly made for a special lens tool. I have tried to put 2 ends of sharp pliers in their and twist, but it didn't open (and I scratched the inside a bit, luckily no lenses).

Does someone have some advice...? Or a (schematic) drawing of lenses in this scope body?
I consider the telescope as a write-off since I've got a new one while getting a new gun near me Gun Store | Guns For Sale Online, but it would be fun to be able to clean it and use it for another 14-15 years

I wonder how spores got inside the scope, never seen anything like this before! As Henry said, it might just be surface deterioting(after all you said yourself that it's bee 14 years already). And yeah, don't underestimate ED50, I've been using mine for solid 8+ years and planning to use it for at least another 8!

 

[dwatsonbirder]

I've just looked inside mine, and noticed something very similar too - cant say it is affecting the optical performance though. What look like water droplets appear to be glue/grease though - the dont move if I shake or invert the scope. Is this a cause for concern?

 

[Markbro]

I've just looked inside mine, and noticed something very similar too - cant say it is affecting the optical performance though. What look like water droplets appear to be glue/grease though - the dont move if I shake or invert the scope. Is this a cause for concern?

If it doesn't affect performance, probably not. Doesn't look like anything organic to me. Did it appear recently?

 

[dwatsonbirder]

If it doesn't affect performance, probably not. Doesn't look like anything organic to me. Did it appear recently?

Thanks - I agree it doesn't look organic. Unsure when it appeared - I only looked after I saw this thread to be honest!

 

[Markbro]

Thanks - I agree it doesn't look organic. Unsure when it appeared - I only looked after I saw this thread to be honest!

Might be just some factory glue on the side or something and overtime due to heat or something it melted and formed this droplet. Really hard to tell from the photos to be fair.

 

[temmie]

Apologies for replying late; I couldn't get myself some time to get the photos from my memorycard.
Hereby, I present you the 'fungus' or whatever it is. It was present for some years but stayed at around 1/3-1/4 of the total surface, and thus it didn't bother me at all as I didn't even notice loss of transmission.
It became a problem however, once it 'grow' to more than 50% of the view.

If anyone wants to guess what this is, let me know!

 

[Binastro]

I have not seen this type of degradation before.

I would have to actually see it.

If the scope is taken apart, one could gently try to remove it.

It looks like some kind of crust.

It seems to have depth.

Regards,
B.

 

[temmie]

Now the next question:
Does anybody know how I could take the scope apart?

A bit like in this topic (but without damaging / breaking something):

Nikon Fieldscope ED50 Separates

I notice this evening that there is a small split between the top and the bottom part of the Nikon Fieldscope ED50 (angle model). All of a sudden the darn thing separates. I notice that the plastic receiver that takes the bolts is broken. The problem is that I don't know how to put these 3...

www.birdforum.net

 

[4John]

Now the next question:
Does anybody know how I could take the scope apart?

A bit like in this topic (but without damaging / breaking something):

Nikon Fieldscope ED50 Separates

I notice this evening that there is a small split between the top and the bottom part of the Nikon Fieldscope ED50 (angle model). All of a sudden the darn thing separates. I notice that the plastic receiver that takes the bolts is broken. The problem is that I don't know how to put these 3...

www.birdforum.net

Temmie,

Can I suggest that you don't take it apart because of the risk of breaking something and instead contact your Nikon dealer or service centre and ask them if they can fix the problem for you ?

 

[temmie]

Temmie,

Can I suggest that you don't take it apart because of the risk of breaking something and instead contact your Nikon dealer or service centre and ask them if they can fix the problem for you ?

Hi John,

I thought about that, but with a buying price of 330 euro back in the days, I would rather opt for a quick opening / inspection, and only if that doesn't work, to contact a Nikon dealer. Nikon isn't known for great customer service, and I can imagine the cost of repair being rather high.

Ofcourse I'm all for repairing (instead of throwing away and buying new), but the scope is 14 years old and I'm not willing to spend more than 1-2 working hours on it. I am a bit afraid it will stay away for a long time, and they will give me a quote well aboven 100 euros...

 

[etudiant]

Apologies for replying late; I couldn't get myself some time to get the photos from my memorycard.
Hereby, I present you the 'fungus' or whatever it is. It was present for some years but stayed at around 1/3-1/4 of the total surface, and thus it didn't bother me at all as I didn't even notice loss of transmission.
It became a problem however, once it 'grow' to more than 50% of the view.

If anyone wants to guess what this is, let me know!

It looks like the silvering under a mirror surface is corroding.
If that is the case, there is presumably some moisture getting into the scope.
Worse, I don't think that it is fixable without some fancy resilvering setup. The entire surface would need to be reworked or the part replaced..
I don't think there is any point in taking the scope apart for an unfixable problem. Better have Nikon handle it, it may need an optics transplant..

 

[temmie]

It looks like the silvering under a mirror surface is corroding.

Thanks but that's not good news indeed. I recently found the Nikon contact info.
I will either bring it to the Nikon repair centre (and they will, according to the website, give me a quote before repairing), or either try to find a second hand ED50 for a good price. I'll keep you all updated, and thank you all for feedback. This forum (at least the optics division) is a gem!

 

[4John]

It looks like the silvering under a mirror surface is corroding.
If that is the case, there is presumably some moisture getting into the scope.
Worse, I don't think that it is fixable without some fancy resilvering setup. The entire surface would need to be reworked or the part replaced..
I don't think there is any point in taking the scope apart for an unfixable problem. Better have Nikon handle it, it may need an optics transplant..

Temmie

I agree with etudiant - something, moisture and/or air, has probably got in the scope. The ED50 is nitrogen-filled to keep out moisture and oxygen. If you take it apart whatever nitrogen is left inside (if any) will escape, so you will need to re-pressurise it with nitrogen after you put the scope back together, otherwise the same thing will continue/happen again. You would need specialist equipment to do that, including whatever connection is used to the injection point. That's another reason not to take it apart ! I agree with etudiant - it's best to ask Nikon to see if it's economically repairable. Nikon is unlikely to clean/resilver mirrors/prisms - they will simply replace them because its quicker than cleaning and labour costs are likely to be higher than parts costs, and they won't have any resilvering facilities. They will have nitogen-filling facilities.

I have no experience of Nikon Belgium's customer service, but Nikon UK customer service was fine when they repaired my ED50's tripod foot when the thread broke (as they used to !).

 

[temmie]

Time for an update!

A friend of mine needed a small scope for travelling, and I allowed him to try and open it, as I deemed it 'written off'.

What he found was not fungus, no oxidation, but... grease! Some grease / oil seemed to have been leaking, coming from the focuser.

In order to open the scope, he opened one of the 3 bolts that could be reached, but he forced the scope body from there. It turned out one of the other bolts was already broken, so in the end, one bolt has been broken in the process of opening the scope. He will now glue it back together after cleaning off the oil from the prism.

Ofcourse it won't be nitrogen-filled anymore, so I give it at max. some years before e.g. fungus will take over. If I was quicker, I could have turned in the scope back in 2019 just before my 10-year warranty was over, but at that time the oil was only at the far outer part of the view.

Attached are 2 pictures from my friend: the first one showes the prism, the second one shows the metal prism holder. The oil went between the prism and the holder and thus was making its way slowly, covering one surface of the prism on approx. 3 years (2019 until present).

 

[Hermann]

Ofcourse it won't be nitrogen-filled anymore, so I give it at max. some years before e.g. fungus will take over.

You're far too pessimistic. For well over 100 years binoculars and scopes were not nitrogen-filled, and the instances of fungus developing were far and few between, unless you lived in a very hot and humid climate. I never had a case of fungus, in none of my optics. And I sure used them in all sorts of weather, and my scopes in particular did get very wet regularly.

What I would do is make sure the scope is completeley dry before you assemble it, and then I would tape the seam between the two body parts. And then you should be set for the nect 15 years.

Hermann