Please help repairing a Nikon focus block

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zzffnn
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Please help repairing a Nikon focus block

Post by zzffnn »

First thank you for checking my thread.

I was trying to equip a Nikon focus block for my son's "micro mineral science" project. But I broke the focus mechanism :cry:

This is the Nikon focus block I have: http://www.photomacrography.net/forum/v ... hp?t=33483

I first noticed that the focus block was slowly sliding downward (both coarse focus wheels seemed tight and working at that time), under 9x NA 0.20 objective. Then, foolishly thinking that I could tighten the focus wheel up (even though I did not find torque control), I twisted the two coarse focus wheels into different directions.

After my twist, one side of coarse focus disengaged completely (no longer worked - even though it seemed to work fine before). And the focus drift downward is now much faster than before. The other side of the coarse focus works only partially now - it still move the block, but makes a squeezing noise now. Fine focus on both sides seem to move but probably are not functional.

My questions are:

1) how difficult is it to fix the focus block now? Should I even attempt it myself (knowing how mechanically dumb I am), or should I send it to an expert?

2) would a kind member guide me through repair here, or maybe even take over the focus block for repair?
I will cover all expenses and provide you my services, if you need it (such as pharmacy consultation, patent law consult, biomedical literature research and English-Chinese translation). Please PM me, if you like.

3) does it sound like I had a cracked fine focus, before I twisted / broke the coarse focus wheels? Is such a (fine focus) repair similar to the fine focus repair of Nikon Labophot? I have some illustrations somewhere, along with an eBay page for a metal replacement, if that is the case.

I am clueless as to what to do now, especially after breaking the coarse focus :cry:

This is too bad, as I already bought over $140 of relevant parts to equip the focus block (without the focus block, those parts won't do much).

Please kindly help us. Thank you again and have a good day.
Selling my Canon FD 200mm F/2.8 lens

Pau
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Post by Pau »

I don't know about Nikon, with Olympus what you did just unscrews the bolt holding the fine focus and it slips because it loses the pressure against a curved washer. You must remove the fine focus knobs caps and tight again the screws, but again this is with Oly, I do this repair very often because the inadequate use done by some students.
Pau

Choronzon
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Post by Choronzon »

You broke the coarse focus gear case / shaft. I probably have parts, but I'm in Seattle now and will be home for 1 day before I leave for Puerto Rico.
I'll pm you when I find out what parts I have. I've repaired hundreds of these as a dealer repair tech.
I am not young enough to know everything.

Smokedaddy
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Post by Smokedaddy »

I can't help you on the course focus. I know you're not supposed to twist them in different directions but you know that too now. I no absolutely nothing about the Optiphot 2, I've never even seen one but I fixed the fine focus on my Optiphot Biological.

http://www.photomacrography.net/forum/v ... sc&start=0

-JW:

zzffnn
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Post by zzffnn »

Thank you, all! Very helpful.

It makes sense to me, that I damaged the coarse focus.

But what about the slowly dropping focus, BEFORE I twisted / damaged it? Was it due to loose screws in fine focus, as described by Pau?

Chorozon,
Do you think the coarse focus is difficult to repair, for a ham-fisted person like me? I found that when I was hungry and in a rush, I tend to do stupid things.......like twisting coarse focus against each other............ :oops:

I am not very good at repairing microscopes - I have a fear of focus mechanisms and complex mechanical stages. For example, I tried, twice, to repair a mechanical stage of Nikon S, but failed to get it perfectly back to normal (it works ok at less than 40x, but not precise enough for 40x and over and some balls would fall out when I use it).

JW's repair photos are very helpful. JW - do you consider your repair difficult?

I don't know how the Nikon focus mechanisms differ, though I do notice that my Nikon focus block has a (slight?) different focus mechanism than my Labophot 2 (which has torque control).
Selling my Canon FD 200mm F/2.8 lens

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