Soldering Flex Cable. How To? - Page 1
Forum section: electronics / projects

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 06:58:04 am
content: I have another Canon Lens broken again, and i know its the flexi cable again! (the 3rd time)Canon should get Darwin Design Awardfor this. I've reconnect previous flex cables by adding and soldering wires on it, but they will not last long, since they always got bended and straighten when the lens zoom out or in, the soldering will get loose and worsen the flex cable condition to beyond repair. Now i've opened this lens and ready to resolder/reconnect. but knowing it will not last long, i paused. I need to have a really good breath on this. So i'll just let the dissambled lens lying there while waiting for better idea on how to effectively reconnect the broken traces in the flex cable. I've googled but mostly in forum that the OP is no better than i am. I hope there are master solderers here with genius idea or links somewhere. I've been soldering for years, but this is the one i've never accomplished well. Please help.

author: flolic
author_rank: Frequent Contributor
timestamp: June 06, 2011, 07:47:45 am
content: What lens is that? You can often get replacement flex cable from eBay for few $$.

author: Armin_Balija
author_rank: Regular Contributor
timestamp: June 06, 2011, 08:35:22 am
content: When solder fails I use neodymium magnets...idk hope it wouldn't interfere with things in the camera itself.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 09:32:47 am
content: Quote from: flolic on June 06, 2011, 07:47:45 amyes i just saw in ebay for the flexi cables parts, that will be last resort if neo-mag still could not work, which could take another 2 weeks to arrive. all the following lenses got that flawed design.1) efs 18-55 f3.5-52) efs 17-55 f2.83) efs 17-85 f3.5-51 and 2 sent for canon repair, will cost me a good $400++, 3 is the picture above. i should get the flex cable part, there's one guy selling for all the lenses above, but from US againQuote from: Armin_Balija on June 06, 2011, 08:35:22 amthis is a joke right?

author: Psi
author_rank: Super Contributor
timestamp: June 06, 2011, 09:48:04 am
content: i once fixed a broken flex cable in a Logitech keyboard by soldering a ultra thin needle on each end of a piece of wire. Then pushing the two needles into the flex cable before and after the break and gluing them in place with silicon rubber.I'm sure there is a better way to do it than that though.Maybe some sort of conductive glue in the crack?With the cable folded like that, you might be able to push a single needle through both cable layers to join the two sides.It would have to be ultra thin though.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 09:55:41 am
content: very good idea! needle! i have some flexi wires maybe i can punch it in there. i already commencing the repair, strip out the insulation. just now i got a pointer on how to fully dissasy the cablehttp://www.pbase.com/barry_2718/efs1785mmexactly the same lens the same problem.

author: flolic
author_rank: Frequent Contributor
timestamp: June 06, 2011, 09:59:00 am
content: Quote from: Mechatrommer on June 06, 2011, 09:32:47 amYou mean cheap "kit" lens? Not worth repairing, just buy new one (if you really need that)

author: flolic
author_rank: Frequent Contributor
timestamp: June 06, 2011, 10:17:06 am
content: Quote from: Mechatrommer on June 06, 2011, 09:55:41 amThat flex can be soldered quite easily if you have steady hand, and very sharp tip on your soldering iron. I learned that hard way when I accidentally cut in half similar flex while repairing customer's 1D MkIIBut that was on a "stationary" cable.Your problem is that that cable is constantly flexing during zooming, and WILL break again on solder joints or right next to it. You need something strong and flexible, but don't know how to achieve that...

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 10:39:37 am
content: Quote from: flolic on June 06, 2011, 09:59:00 amyou certainly have a very good picture! yes i sent both but canon asked $800 for both, since they know i've dissambled the lens before that, so i only repair the 17-55 at $400, nearly half of its cost. i'm looking for another cheap kit right now, or perharps L series, with this bad experiences, mid range lenses is not worth it i think.Quote from: flolic on June 06, 2011, 10:17:06 amand again you have a brilliant imagery of it! i will not solder at cracked join, somewhere farther up and down from there, i've done that its tricky job, but the solder contact area is too small (we talking fine pitched flexi here <=0.5mm with pretty good but sensitive insulation) and get loose soon after.edit: i dont think needle is doable, i just had a good look just now

author: flolic
author_rank: Frequent Contributor
timestamp: June 06, 2011, 11:49:54 am
content: Quote from: Mechatrommer on June 06, 2011, 10:39:37 am17-55 f2.8 is wonderful lens optically, but mechanically is a piece of crap. What is a shame, because it is very expensive.After spending too much money on a sub quality optics, I upgraded all my lenses toLand now enjoying optical quality and robustness.Quote from: Mechatrommer on June 06, 2011, 10:39:37 amNow I remember that I just to have very thin and very flexible braided (litz) wire. IIRC,wire was from old and big computer tape data recorders from 1970's. They used that wire to connect recording heads to supporting electronics. Despite looking very fragile, you could bend that wire for a thousands of times without any damage...So, if you can find something like that, that could solve your problem

author: RuddyCrazy
author_rank: Newbie
timestamp: June 06, 2011, 11:58:52 am
content: If the canon are so shodding with flex cable why bother using a canon in the first place GET a real camera.....

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 12:06:10 pm
content: Quote from: flolic on June 06, 2011, 11:49:54 ami dont care much about quality, as i'm more prone to sharpness and color saturation, which pretty looks the same to me between low and hi L range, given the same original brand of canon, not sigma or tamron or all that crap. the only difference is the fastness of the lens, bokeh and durability which is yet to be seen. what concern me now is profit vs investment. i have 70-200 f2.8 L which still standing strong, just because i seldomly used it. if this L lens exhibit the same fate later on, then i will no doubt 100% move down to all super cheapo canon lenses, which is expendable after several session of photography which can easily covered by the profit gained.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 12:07:23 pm
content: Quote from: RuddyCrazy on June 06, 2011, 11:58:52 amname? dont tell me canon, nikon, sony or fuji. they are all the same scams!

author: Unknown
author_rank: Unknown
timestamp: June 06, 2011, 01:22:47 pm
content: For better mechanical robustness you can try adding a small and thin piece of circuit board and soldering the contacts on that. A harness can then hold the flex cable in place on the pcb and you can solder bigger wires on the pcb as you have the pad support now. Kind of like a flex-rigid PCB. You can probably make a custom PCB from a copper clad and a dremel and time.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 01:29:22 pm
content: sounds like more space needed. when assembled, the cable is contained in a very tight space. and since its just right next to mechanical zoom movement, any protrusion will block the movement or damaging the additional parts/pcb. but nevetheless, a good idea.

author: tekfan
author_rank: Frequent Contributor
timestamp: June 06, 2011, 02:16:10 pm
content: Quote from: Mechatrommer on June 06, 2011, 12:07:23 pmHasselblad, Leica, Zenit, Nikon F series... I know, I know, these are all old film cameras but atleast almost every single part is made out of metal. No flex cables, just heavy mechanical threads for manual focus.

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: June 06, 2011, 07:52:19 pm
content: Quote from: tekfan on June 06, 2011, 02:16:10 pmNikon F5 uses flex cables. F4 uses flex cables as well. The last mechanical one that does not have a flex cable is F3 as far as I know.I am sure Hasselblad that was used on the Moon did not have any:NASA also used Nikon F3 in early Shuttle flights and even lost a few in orbit:Zenit?!What piece of shite they are!

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 06, 2011, 08:51:05 pm
content: Quote from: Leo Bodnar on June 06, 2011, 07:52:19 pmif that is the so called "real camera" i should have. people will call me freak!

author: Leo Bodnar
author_rank: Frequent Contributor
timestamp: June 06, 2011, 09:13:33 pm
content: Quote from: Mechatrommer on June 06, 2011, 08:51:05 pmDon't be silly. This is Nikon F3 - the camera that is possibly responsible for more striking press images of the 20th century then any other.Manufactured until 2000.And regarding the optics quality - Nikon was manufacturing lenses for Canon cameras before WW2 until they became competitors.

author: tekfan
author_rank: Frequent Contributor
timestamp: June 06, 2011, 10:46:21 pm
content: Quote from: Leo Bodnar on June 06, 2011, 07:52:19 pmCome on! They may not be the best cameras but are definetly not the wrost. Atleast for Russian standards.You can actually get pretty nice resuits with a Zenit E and a Helios 44-2 58mm lens. Later on I bought a Canon SLR. The pictures didn't even come close. By then the Zenit's seals around the film compartment started to leak light so I taped electrical tape around it and it worked a treat. Then digital cameras became affordable enough and are far more practical.Well the later Zenits really were shit when they started to use plastic.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 07, 2011, 01:16:25 am
content: Quote from: Leo Bodnar on June 06, 2011, 09:13:33 pmthat was history. today is today. autofocus is prequisite, not like before. i choosed canon over nikon for some "personal interest" reason. nikon is good no doubt, but its not my type, simple as thatand today, as i said they just the same producing "design for the dump"

author: Comeinhandy
author_rank: Newbie
timestamp: August 05, 2014, 08:22:23 am
content: This video on soldering wires onto flex cable might help some:http://youtu.be/FzqIoq8LEEc