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05-30-2013, 09:37 PM   #1
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Help!! Sigma 24-70mm EX DG

Ok so recently my lens took a fall and pretty much stopped working and opened up at the aperture ring.

After further inspection a screw had come loose, but still noticed other issues like no AF, focus ring was whacky and didn't turn right, aperture ring didn't spin etc.

I opened it up and kinda got things all good now except one major (or minor depending how you see it) issue.



The little connector cable thing ripped and it pretty much stopped the circuit hence why my K-5 II can't read the lens or communicate with it at all. What I'm thinking is that I'll have to solder a wire from one pin end to the other (for whichever one the broken link corresponds to). Any suggestions if this is a good idea? BTW yes I know those are accidental smears while working with it, already wipe em clean with a lens pens :P

I can now use the lens again but in AV, albeit I get pretty much no EXIF other than shutter speed. Any ideas on how to get the aperture ring to work? As soon as I hook up the lens to the body it sets at 2.8 and even if I turn the aperture ring it stays at 2.8 =/

Greatly appreciated

05-30-2013, 11:51 PM - 1 Like   #2
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It seems a straightforward repair to me. If you have some soldering skills (and a good solder) you should be able to place a jumper between the two points of the only path that got broken. Use a small (monofilament wire) and glue it to the ribbon so it will not move.

The broken link (4) will be replaced by soldering a wire between (1) and (2). electrical contact of pin (1) must be under the ribbon or under the white plastic housing. Glue the new wire to the ribbon (3)

Last edited by carrrlangas; 06-14-2013 at 12:07 PM.
05-31-2013, 06:33 AM   #3
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Seeing that big scratch on the rear element and for sure the alignment is going to be off after a bang like that you should just trash it .
05-31-2013, 06:48 AM   #4
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it's not a gash, just a small smear that I cleaned up already.

05-31-2013, 09:32 AM   #5
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QuoteOriginally posted by carrrlangas Quote
It seems a straightforward repair to me. If you have some soldering skills (and a good solder) you should be able to place a jumper between the two points of the only path that got broken. Use a small (monofilament wire) and glue it to the ribbon so it will not move.

The broken link (4) will be replaced by soldering a wire between (1) and (2). electrical contact of pin (1) must be under the ribbon or under the white plastic housing. Glue the new wire to the ribbon (3)
Thank you! I'll be trying that this weekend, let's see how it works
05-31-2013, 02:21 PM   #6
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QuoteOriginally posted by capsloc Quote
Thank you! I'll be trying that this weekend, let's see how it works
Maybe you already know but Just in case: Use a 20W soldering pen (is it called like that?) make sure the tip is in good condition and use a light, thin cable leaving as little excess as possible. Glue it with not too strong glue (to avoid damaging the ribbon)
And show us a picture of how it looks!

Last edited by carrrlangas; 05-31-2013 at 02:38 PM.
06-10-2013, 01:07 PM   #7
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hey! You never got back to us. Did it work??
06-20-2013, 03:19 PM   #8
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QuoteOriginally posted by carrrlangas Quote
hey! You never got back to us. Did it work??
All late, but finally getting some time tonight to get things rolling. Finally settling in to our new house so let's see how it goes. I'll post pictures and results after the surgery on the lens haha.



06-21-2013, 05:44 PM   #9
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If you decide not to try the repair it yourself, you might contact Sigma Repair. The use a outside company for lens repair, but the info is on their web site. Back in my Canon days I cracked the barrel on my Sigma 24-70, which was several years out of warranty. I sent it in for a estimate which was much cheaper than I feared. After giving the OK to repair it I had the lens back within a week. They cleaned and returned the lens to spec's.
Another plus, the lens always had a slight front focus error, which I learned to live with. After getting the lens back the focus was perfect, wished I had sent the lens in for adjustment years ago. When I sold it along with my 5D someone got what amounts to a new lens.
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