Disassembly – Vivitar 70-210mm F4.5 (Kobori)

Vivitar 70-210mm F4.5 lens version made by Kobori has interesting mechanical construction of aperture transmission. I recently disassembled one sample for repair.

As usual first step is to unscrew four mount bolts and remove thick and massive mount ring.


Click-stop mechanism is self secured, so it’s safe to remove aperture ring without loosing tiny metal ball (or pin). Just watch the aperture limiter transmission lever while pulling out the ring.


Next step is to unscrew four black bolts from the central area of black focus distance scale cylinder. Then simply shift that cylinder under the focus/zoom ring.


Unscrew four black bolts in areas indicated below, and remove mount area frame. Remember that aperture limiter controlling pin should be visible the big opening near “Made In Japan” sign while assembling back.


Now the problem is clearly visible – the tiny black spring is disconnected from second aperture transmission lever. And that lever ir moved to the wrong position. It’s nice to see the bearing system for smooth lever movement.


Be careful with that tiny spring, hold it firm with precise tweezers, connect into position pictured below. I’d recommend some additional glue securing of spring ends, because they may easily fall off again when lens is under stress hit or shake.


This look reminds me something… ah yes it looks like an anti tank grenade : )


It’s time to assemble lens back in the opposite order. Make sure aperture transmission lever is positioned on pin while attaching aperture ring.


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