18-200VR finally died.....


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lsisaxon

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Nov 29, 2004
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After having intermittent problems like jammed SWM, intermittent VR for quite a while, my copy of 18-200VR finally died.

When I took it out of the dry cabinet to test before I bring it out to SBG, the lens refused to focus down to anything below 1m. It just got stuck.. So, hoping to be able to undo the jam, I exercised the lens a bit by manually turning the focusing ring and the zoom ring to and fro...... then it got worse... the zoom ring also got stuck..... :sweat:

Time to open up the lens to see what's causing the jam... My worst fears came true... The VR flex is the culprit of it all.



I stripped past the PCB to unveil the flex dressing. The lens cannot be used with the crumpled flex jamming the mechanism. So I continued to strip until I can at least get the flex out. Then I saw why the flex could fail. It was designed to fail!!!

The flex comes out from a slot on the optical tube assembly.


The slot edges are not rounded enough. Plus there is another tube which slides on the inside, so the flex is making a u-turn plus another step to the outside tube. This stresses the flex and will cause it to dislodge from the tube if the glue gives way like mine probably did. So when you zoom in and out, there will be tremendous movement on this flex.


Lastly, the focusing lever slides over the flex when the distance is <1m.


With these multiple mode failures, it is no wonder my most used lens gave way.

A word of caution to all users of this lens, when you zoom, zoom gently so as not to stress the flex too much.

Let's see if NSC is kind enough to offer me a free service for the failure of this flex.
 

glenncain

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May 23, 2006
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ooo thats a good insight to the innards of 18-200. seems like alot of ppl including myself may be culprit to hard zooming
 

Leong23

Senior Member
Oct 18, 2007
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within myself
Thanks for sharing this, hopefully mine 18-200 will be ok....
 

fann01

New Member
May 3, 2008
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Wow u sure know how to take out the pieces bit by bit. Hope nikon is reading this thread. :)
 

PreciousP

New Member
Feb 21, 2008
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I think you mean <1mm

Nikon would be kind enough to offer you a job as design engineer :bsmilie:
No he meant 1m, that when the lens is focused to less than 1 m, the mechanism slides over the flex.

Wow, such design is doomed to failure, a matter of time!

Just when I thought I would be buying this lens...
 

Dearboy87

Senior Member
Jun 7, 2007
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once i was shooting with 18-70mm... the lens refuse to focus anything far.. anything futher than approximate 6-7metre..
 

Six-GHz

Senior Member
Nov 29, 2006
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Sorry that your lens died, but thanks for your interesting post. This is my first glimpse of the $1200 innards! Pse share on what NSC has to say about this.
 

La Fontaine

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Jun 12, 2008
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Jalan Poonpipi
Well, I guess that VR might not be designed to be that lasting.

What about SWM, I am not that sure. And then, coupled with a very long zoom range, don't expect it to last very long.

I prefer to stick to the old school screw driver AF and then, rely on my muscles for VR.:bsmilie:

I have the impression that some of those very old lenses are more robust and well designed and built, and built to last.
 

iceecold

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Apr 3, 2007
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Yo ISISaxon!!!

sorry to hear your lens spoilt!!! in bkk now working my butt off... eh you got any letters from ns or not har??? like a bit too quiet... too quiet for comfort... call u when i'm back...

DO
 

lsisaxon

Senior Member
Nov 29, 2004
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Thanks for sharing this, hopefully mine 18-200 will be ok....
One tell tale sign of the flex giving way is when you hear a 'flik' sound when the focusing goes down to <1m. This will mean that the focus lever is already brushing against the flex which might be caused by the glue giving way and the flex is no longer flat against the tube.

If this happens, better to send your lens in for servicing. Don't wait till the problem becomes as severe as my case because it will probably cost a lot more. It's definitely not easy to strip past the tube assembly to reach the VR board if the flex needs to be changed.

I reiterate.. zoom gently with this lens. ;p
 

lsisaxon

Senior Member
Nov 29, 2004
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I think you mean <1mm

Nikon would be kind enough to offer you a job as design engineer :bsmilie:
No.. it's the 1m mark. The lens can focus down to 0.5m, but mine got stuck when it reaches 1m.

Too bad I'm an electronics engineer, not a mechanical engineer. But I think they should have rounded the edges of the slot and the inner tube where the flex emerges from the barrel so that the flex doesn't have to go through such a sharp angle. As for the focusing lever, tapering the edge which would go over the flex so that in the case where the flex dislodges and becomes slightly higher, the lever would still glide over the flex smoothly and not get obstructed by it.

I haven't opened the MiT copy, so I don't know if the design has been improved in the MiT version. ;p
 

lsisaxon

Senior Member
Nov 29, 2004
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Here are some more pictures of some other parts.

The SWM.


The CPU board, the flex with the accelerometer for vertical and horizontal motion sensing (I think), the contacts for the focus and zoom encoders (the zoom one is the smaller one with very fine fingers.. I think I crashed it when I zooming in and out quickly when I was trying to resolve the jam. Some of the fingers looked bent when I was taking it out, then they broke when I tried to bend it back. ;p


The zoom and focus encoders on the barrel.


The broken VR flex.. tsk tsk tsk..
 

Wzierbovsky

Member
Jul 2, 2004
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Singapore
Really fascinating breakdown and insightful read; much thanks.:)
 

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