Tokina RMC 90-230/4.5 (OM): Minor service

Andreas Thaler

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Joined
Nov 19, 2017
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4,209
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Vienna/Austria
Format
35mm
I received a zoom lens for a whole EUR 10,- (~ USD 11,-)

I found it on willhaben.at, the largest online platform for used items in Austria.

It was offered there with a few dim pictures:

Lens is untested and therefore declared defective. No guarantee or returns.

„Another repair project“ I thought to myself and prepared myself to order a wreck.

„If the bayonet ring is so dirty, what else would it look like?“ I thought.

After having received the zoom lens I unpacked it and was amazed.

An almost new piece stood in front of me. Apart from the bayonet ring, clean, no scratches and almost no dust on the lenses.



Gorgeous!




There is also a current Hoya UV filter, also in mint condition.

What a zoom!

All metal, heavy, no extension of the tube when moving through the impressive focal length range.

Focusing and zoom path are smooth, the aperture catch clicks brightly.

No issues detectable.


With joy …

... I started cleaning the bayonet ring and the area underneath.



How this greasy stuff came about - I don't know.




Removing the bayonet ring

After loosening the three bayonet ring screws, this spring connects the ring and tube.

It needs to be unhooked.




Under the bayonet ring






Bayonet ring removed, the arrow points to the spring retaining screw.






In order to be able to clean the ring more effectively, I remove the hood to the rear lens.








Zippo lighter fluid cleans things up.
 
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OP
OP

Andreas Thaler

Subscriber
Joined
Nov 19, 2017
Messages
4,209
Location
Vienna/Austria
Format
35mm






Minor areas of rust ...










... which the Dremel Stylo with an attached stainless steel round brush takes care of.




Where the Dremel can't reach, the files take over.




Slightly rusted areas can still be seen deeper in the tube.




I don't want to dismantle the lens any further.

So I apply some Ballistol Universal Oil to dissolve the corrosion and protect the areas.


That's all folks - assembly!




After having tried unsuccessfully to attach the spring to the bayonet ring with a probe and tweezers, I came up with the simple solution:

Simply hold the ring over the tube and pick up the spring with the small retaining screw.






The hood pushes the spring to the side.

Now the tension of the spring is correct and the aperture blades close completely.




After mounting the hood, there is a problem when I press the stop button on the lens to set the smallest aperture.

I use the probe to lift the spring a little and now it fits.
 
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OP
OP

Andreas Thaler

Subscriber
Joined
Nov 19, 2017
Messages
4,209
Location
Vienna/Austria
Format
35mm






Cleaning the front and back lenses.






Aqua Purificata removes the dirt from the front cover.






Clean




Everything works, the focus adjustment is correct.




By the way, the Olympus OM-4 can be triggered mechanically at 1/60 second without a battery.




The table always fills up quickly


+++

All information provided without guarantee and use at your own risk.
 
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xkaes

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Joined
Mar 25, 2006
Messages
4,470
Location
Colorado
Format
Multi Format
Thanks again. Coincidentally, I have a for Olympus very nice, compact, Makinon 135mm f2.8 with a stuck-open diaphragm that needs surgery. I mentioned this is another thread, and these shots show me what I'm dealing with -- exactly.

I'll give it a try, but I might no be as lucky as you.
 
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