How I fixed a dropped AFS ED 28-70 F2.8


fatigue

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Sep 26, 2005
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#1
A special request

First, let me show my bench. ESD mat properly grounded




1.Remove the screws indicated by green arrows
2. Remove the black plastic rear cover indicated by pink arrow
3. Remove the mount screws indicated by red arrows (no need to remove the single screw that is located at 10 o'clock )



Sorry, a bit out of focus again ( get ready David for Etegration's comments :bsmilie: )


4. Remove the mount
 

fatigue

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#2
5. Remove the screws of the zoom slider


6. Turn the zoom ring, while carefully lifting the slider to separate them from each other


7. Lift the zoom ring


8. Carefully remove the slider


8. Remove the 3 screws
 

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fatigue

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#3
9. Carefully lift the rear casing and you will see the 2 wires for AF/MF switch


10. Desolder the wires


11. remove the rear casing


12. Loosen the screw that holds the PCB. Be careful not to loose the plastic washer/insulator under the PCB


13. Remove the focusing ring. There is a spacer and a sort of a spring, don't forget the sequence
 

fatigue

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#4
14. Remove the 6 screws that hold the front casing


15. Remove the front casing.


16. Move zoom lever (yellow arrow) until you can see the screw (green arrow)
Note: to prevent damage, I use a wooden chopstick to move the zoom lever :bsmilie:



17. Remove the 3 screws indicated by green arrow.
Note: 2 other screws located on the other side of the barrel.
Don't remove the other 3 smaller screws
 

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Zichar

Senior Member
Apr 22, 2008
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#9
Interesting series ... rarely get to see pics of the insides.
But sheesh, all that for 2 small 'washers'?
And from my experience, taking things apart usually not a problem ... putting them back together, brrrrr
 

luna_sea83

Senior Member
Jul 17, 2005
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#10
Great guide you have there friend, but i guess most of the people here would still have you to get their lens repaired instead :bsmilie:
 

ZerocoolAstra

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Mar 13, 2008
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#11
thank you so much for sharing the photos!
I now appreciate the complexity of the work you do so much more!
Though I like to be hands-on (minor repair of car parts, stereo, etc), I think this looks like a process where something could go wrong and mess up the whole thing.
As Zichar mentioned, taking apart the lens might be fairly smooth. Putting it back together is the part that frightens me!
 

ZerocoolAstra

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Mar 13, 2008
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#12
Just wondering if the grounding mat and connectors to the body are really necessary, in your opinion.
I've repaired a number of PCBs (with capacitors on-board), and never had a problem with static or any stored charge causing a problem later on.
 

yyD70S

Senior Member
Dec 25, 2005
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#13
If we could have a sticky for the various David's DIY project N.

yy
 

giantcanopy

Senior Member
Feb 11, 2007
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#14
great documentary :thumbsup::thumbsup::thumbsup:

but myself doing soldering desoldering is .. unimaginable. i think .. most of us will still refer to u if we run into any problems

ryan
 

fatigue

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Sep 26, 2005
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#15
Just wondering if the grounding mat and connectors to the body are really necessary, in your opinion.
I've repaired a number of PCBs (with capacitors on-board), and never had a problem with static or any stored charge causing a problem later on.
It's standard operating procedure and I don't want to take the risk ;)

Honestly, you're right. With humid conditions here in SG plus I always walk around the house (or should I say flat) barefooted, chances of ESD damage is slim.
 

fatigue

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Sep 26, 2005
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#16
Interesting series ... rarely get to see pics of the insides.
But sheesh, all that for 2 small 'washers'?
And from my experience, taking things apart usually not a problem ... putting them back together, brrrrr
Yes, taking things apart is the easy. Putting them back in one piece is a headache.
Putting the mount back is a bit tricky. You need to slot in the aperture lever inside a mechanism being held together by a spring.

Behind the plastic white bushing are screw washers that does not stay in place.
Although the bushing fits exactly at the gap, the washers will fall in the process of reassembly
Here's my trick:

 

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Benji77

Senior Member
Feb 18, 2006
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#17
Phwah. You make it look so simple.
Stripping something (or someone;)) is always the fun part. But putting things back....ermmm......:bsmilie::bsmilie:

:thumbsup: well done!
 

May 9, 2008
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#18
Very off topic, but does this 28-70 f2.8 lens have any mechanism to prevent water leakage? I would rather hear from a person who actually take these things apart rather than go by publicity material of the manufacturers.
 

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