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I ruined my new (to me) AF Nikkor 80-200mm f/2.8D


chulster

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Been wanting one of these two-ring AF-D 80-200mm lenses for ages. Finally found one at a price I was comfortable with: $160, with non-working autofocus, but otherwise dandy. The M/A ring switch was stuck on the M setting. Thought I could fix it, and, in fact, with the help of

, I almost did. But actually wound up making it worse.

 

The problem with this copy was not the one discussed and solved in this venerable thread. Had to do a fair amount of disassembly, but finally got to the bottom of the issue (the previous owner had attempted to superglue the cracked A/M ring and failed, only managing to glue it to the barrel such that it couldn't be turned). I removed the old glue and did a slightly better job of mending the broken ring, restoring the ability to turn it to the A position. I could see by turning the AF drive shaft that it was going to work. Hallelujah.

 

I was almost done reassembling the lens when disaster struck. Because of carelessness, the flex cable leading from the CPU to the contact pins at the mount tore. One wire was severed clean. Hoping against hope, I taped the flex together, finished reassembly, and mounted the lens. No dice—the camera couldn't "see" it.

 

So now I have a lens that, before my botched repair, had been manual-focus only but otherwise fully functional. And which is now still manual-focus only but, also, effectively a non-CPU lens. Just desserts.

 

I'm not giving up, of course. The first thing I did was get on AliExpress and search for a replacement flex cable. Found one; only problem is it costs $139. That's because it's not just the flex I need, but basically all of the electronic and electrical parts of the lens in a single, complex, winding piece.

 

In preference to spending nearly what I spent on the lens itself for this part, I'm going to try and mend the torn flex cable. I'll have to buy a soldering iron and some solder. If that fails, I can still buy the $139 part (although the thought of installing it is a bit daunting). Even with that cost added, the lens would still be a bargain, if much less of one than it had been.

 

Does anybody have any advice that may help me succeed in the soldering job? I have seen a couple of YouTube videos about repairing torn flexes, but they deal with ones that were completely severed, whereas only one wire in my flex is cut. I'm anxious to repair it without harming its neighbors.

Edited by chulster
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Those flexible 'cables' are a total PITA! The copper track is encased on both sides in a plastic insulation that melts easily under the heat of a soldering iron.

 

You need to scrape away the insulation on the thinnest side using a craft knife, until you see metallic copper plainly revealed. Use the thinnest wire you can find to make the repair 'jumper'. Usually a single strand of multistranded wire is sufficient.

 

Don't try just to bridge the broken track with solder. That won't work - or at least not for very long.

 

Set your soldering iron at the lowest temperature that'll just bead up a fine solder-wire. Tape the two split parts of the cable together on the thick side, opposite your scraped and prepared tracks. Tin one end of the strand of wire that's needed for the jumper in preparation. Leave yourself a good length of wire so that you can easily position the tinned end on one of the broken tracks.

 

Then mentally cross your fingers and go for it! Solder the tinned wire end to one side of the broken track - very quickly before the whole thing melts. Let the solder solidify while holding the repair wire in place. Now cut a very short length (1.5 - 2mm) of wire off next to the solder joint you've just hopefully made. Push the free end into close contact with the other side of the broken track and apply solder and iron together. Voila! ...... or not.

You now have either a repaired track or a melted mess.

 

Assuming a good repair; it'll need some additional tape support to stop it fracturing as it flexes.

Edited by rodeo_joe|1
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Chulster, For me this kind of repair is insane. I think I would need a beta blocker as much to steady my nerves as my hands and I would expect to fail anyway. The two ring version has been out and is still sold new since 1997. I sold my one touch in 2002 when I bought the two touch used with a broken focus select ring that I eventually had replaced. I have the version II 70-200 AFS 2.8 but the 80-200 remains my favorite. It’s very sharp and allows me to use old style extension rings. I would be more inclined to purchase a new circuit but my perspective is that time is something I tend to have less and less of just by the nature of things. My next lens in the 80-200 range will no doubt be dedicated for a future mirrorless body. I think the 80-200 is a great lens.

Good luck.

Edited by 2Oceans
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Those flexible 'cables' are a total PITA! The copper track is encased on both sides in a plastic insulation that melts easily under the heat of a soldering iron.

 

You need to scrape away the insulation on the thinnest side using a craft knife, until you see metallic copper plainly revealed. Use the thinnest wire you can find to make the repair 'jumper'. Usually a single strand of multistranded wire is sufficient.

 

Don't try just to bridge the broken track with solder. That won't work - or at least not for very long.

 

Set your soldering iron at the lowest temperature that'll just bead up a fine solder-wire. Tape the two split parts of the cable together on the thick side, opposite your scraped and prepared tracks. Tin one end of the strand of wire that's needed for the jumper in preparation. Leave yourself a good length of wire so that you can easily position the tinned end on one of the broken tracks.

 

Then mentally cross your fingers and go for it! Solder the tinned wire end to one side of the broken track - very quickly before the whole thing melts. Let the solder solidify while holding the repair wire in place. Now cut a very short length (1.5 - 2mm) of wire off next to the solder joint you've just hopefully made. Push the free end into close contact with the other side of the broken track and apply solder and iron together. Voila! ...... or not.

You now have either a repaired track or a melted mess.

 

Assuming a good repair; it'll need some additional tape support to stop it fracturing as it flexes.

 

Omg, it worked! Oh frabjous day!

 

I tried to use a thin wire to bridge the separated trace ends, but try as i might, I could not get the piece of wire to stick while applying solder. However, I was left with a nice-looking layer of solder that fully covered the exposed parts of the trace where I'd scraped the plastic away. It looked solid enough, so I covered it with tape and put the lens back together. Mounted it on the camera—it works! Now I have autofocus and everything!

 

Btw, I understand now why the flex cable tore in the first place. The problem is there is extremely little clearance under the tripod collar where the cable has to fit. When sliding the tripod collar back in place the first time, i didn't notice that it had snagged on the flex cable. I applied a little pressure and ripped the flex.

 

After doing the repair, I put some scotch tape over the mended part of the flex. Then, when putting the tripod collar back, there was even less room between it and the cable. It was a very snug fit, and indeed a bit of the tape bunched up as I slid the collar over it. The flex cable, though, seems fine.

 

Thanks again for your advice, Joe!

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