Flat Flex Cable Repair - Can we save our aging FFCs?

Video sponsor: PCBWay: $5 for 2 layer PCBs with 24hr turnaround at www.pcbway.com/
One problem we often come across when repairing a vintage computer is a bad FFC, a Flat Flex Cable. These cables are made the same way as flexible PCBs but have the contact fingers exposed on the ends and typically some sort of plastic stiffener sheet glued on.
With age the fingers sometimes come loose which leaves your repair stuck until you can locate a good used cable. Many of the cables and connectors they used are no longer available as new replacement parts. So, a damaged cable can leave an otherwise working system out of commission.
Being faced this this problem recently I tried to come up with a way to repair these cables. Join us as we see how it worked out.
Timeline:
00:00 - Welcome
01:24 - Effect and Cause
03:24 - Idea to implementation
09:16 - Initial results
12:39 - Testing
13:56 - Conclusion
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Credits
Chiptune Thing No. 3 "Victory" by Steven O’Brien / stevenobrien
Creative Commons - Attribution 3.0 Unported- CC BY 3.0
creativecommons.org/licenses/b...
Music provided by Music for Creators • Chiptune Thing No .3 V...

[@3vi1J]

Very informative, Jeff. I'll have to keep this in mind for review the next time I see a cable issue like that. Thanks for sharing your experience.

[@minombredepila1580]

Very nice and illustrative video mate. I will use your always good ideas & techniques for my repairs, as fixing a Spectrum keyboard FFC !!!. Your channel is so good and unfortunately so underrated!!!

[@PoseidonXIII]

I love the vibe of your videos man. Feels like something I'd catch on PBS back in the day.

[@vanta6lack]

Thanks for the video from Ukraine. I was disassembling my printer the other day and was careless enough to have messed up the fingers of a ribbon cable. Now, I'm gonna buy some superglue and see how it'll turn out!

[@johnhorne2576]

You have just removed 3 days of stress!!! GENIUS!!! I have a Bluetooth speaker with two damaged cables and cannot source them so I am gunna break out the super glue n tape. Full confidence after your tutorial. Thank you for this upload!!!

[@HeyBirt]

Good luck with your repair

[@patricpdp7380]

Best video in KZbin to repair the FCC cable. Thank you. I hate you fcc cable

[@tusharroy753]

Nice and helpful information. This might help lot many people.

[@devicemodder]

Glad I found this video. I'm having peeling flat flex issues in a sony video8 VCR. Gonna have to try this

[@RestoreTechnique]

Nice tutorial :)

[@iz8dwf]

good job Jeff!

[@j.d.3269]

Perfect! Subscribed.

[@ctecrwp]

That was so helpfull. I have couple of flex cables that are hard to find. I belive I can make them work again...👍

[@SurprisedTeaCeremony-dc3uy]

Thanks for sharing your experience! I have a flex cable where the blue stiffiner fell off. I saw in the comments that in can be glued back on, unfortunately I lost mine... My question is if I can buy a sheet of this material ? Just the blue plastic around 8 or 9 thousandths thick. Thanks.

[@Fezzler61]

Slick work! I have nowhere near your level of skills or experience in this arena. I can say that I have been disassembling, cleaning, and doing very minor repairs vintage computers for more than 20 years and in my recollection that darn Model T 102 keyboard cable is the most troublesome ribbon connector I have ever stumbled across. Most ribbon cables I've dealt with have the clamp-like connector that loosens the pressure on the ribbon for safe removable and clamps down for tight fit on replacement. The ones that I have dealt with that are similar to the 102 keyboard connection, the ribbon leads where just not that flimsy. Your modern solution mention below would be welcomed I'm sure by the retro computing world.

[@HeyBirt]

The connectors used on the T102 are problematic and so far no one has found a connector with similar footprint. Hopefully we can figure something out.

[@GadgetUK164]

Great job =D I've done the same sort of thing before and it is reliable - I didn't think of masking off with kapton tape though =O

[@HeyBirt]

The tape does not make a perfect seal but it keeps most of the glue off the contacts. Using your wonderful fiberglass pen takes care of the small amount that leaks through.

[@anilarora5099]

Very nice Jankari Kay liya Thanku Sir @

[@sajalkantisarkar6134]

I will try again tomorrow

[@wimwiddershins]

I have an Atari LYNX II flex with rubbed off carbon/graphite contacts on the ribbon. Its a right P in the A to fix. I think replacement is the only reliable option.

[@HeyBirt]

The carbon contacts are defiantly a problem. GadgetUK trims 0.5~1mm off the end of such a cable so that when it is plugged back in you have some new carbon to connect to. If you have the extra cable length this might work.

[@NumosG]

Since pcb manufacturer are now offering more and more flatflex options, I wonder if that is a viable solution to replace broken flex cables and manufacture the custom ones for our old computers. Like, designing the pads and the traces and the dimensions like the old cable, only traces, no active components. Have you tried that already and I just missed it?

[@HeyBirt]

Having a cable made is possible it may or may not be economical depending on application, i.e. if you only need one. If you are lucky you might find an off the shelf FFC that is close enough. There are some folks getting cables reproduced for some machines, where they can get a large enough batch made to bring the cost per cable down this is a good option. For the T102 shown here the connectors are a problem as nobody has been able to find an FFC connector with same footprint. The connectors are often the source of the problem, as it was in this case.

[@jeffreyphipps1507]

I've never worked on these cables, so this is a wild suggestion. Clear nail polish dries slower and you could put a layer underneath lifted contacts and a layer over the top. then sand off the contacts like you did at the edges. Then again, it might not work. I don't know.

[@SurprisedTeaCeremony-dc3uy]

I would like to hear how that works! Nail polish already is a secret weapon in my toolbox.

[@austinbentley6234]

Would you be able to do a video on steps to do before booting on a vintage computer for the first time? I'm scared to death to turn on this old commodore, thinking something might pop. I know that these power supplies sometimes skew off on the voltage.

[@HeyBirt]

Hi, I have already started a video series like this. Check out this playlist: kzbin.info/aero/PLegscpHOheJt_EpuPs9hfBpOJ5elRhYvw

[@austinbentley6234]

@@HeyBirt nice. Much needed in the vintage community to avoid dingus like me from ruining hardware. Thanks!

[@2591BigT]

Do you think that I could fix my hp officejet 7612 electron cables. one on is damaged.?

[@HeyBirt]

Well, it the flex cable is already damaged it won't hurt to try and repair it.

[@showbread9366]

Why does it matter if it’s attached on only one side? Couldn’t you just dip it in some kind of acid solution to leave the wires exposed & insert it to the board with a thin piece plastic on one side wedging it tightly?

[@HeyBirt]

I made this video months ago so I'm not entirely sure what you are referring to when you say "Why does it matter if it’s attached on only one side? " Dip what in acid? The flex cable? To dissolve the polyamide backing? I'm not sure what that would gain you even it if would be possible to dissolve the polyamide without dissolving the copper. Keep in mind the copper traces are only about 0.004" thick they can't be inserted into anything on their own.

[@DavidPlass]

Sadly my 102 keyboard cable just gave up the ghost and the entire stiffener came off. Is it possible to glue the whole thing back on? (Or, maybe better, replace the whole cable?)

[@HeyBirt]

You should be able to glue the whole stiffener back on. I did find some new KB cables, but the minimum order quantity is 1,000 pieces. I'll keep looking though.

[@DavidPlass]

@@HeyBirt I'll try gluing it, thanks. This cable has been "snowplowed" so I'm not super confident it will work. I'm going to order some 20pin cables Just In Case.

[@deamondeathstone1]

And if this way is a no go? Desolder the connectors and use Male/female dupont wires?

[@HeyBirt]

I'm not too thrilled with the quality of dupont connectors. Even in a temporary application they can be very fussy. A friend and I have been chatting about a solution to these particular T102 cables/connectors to replace them with something modern.

[@bobweiram6321]

I hope you eventually figured out that in most cases, you can simply press an iron to adhere those pins.

[@HeyBirt]

Never had any luck with that.

[@ErikBongers]

That's a Sherline vise!

[@HeyBirt]

Good eye, yes it is.

[@scottmcdonnell7559]

Weird.... Why do you keep deleting my comments trying to help people find these cables?

[@HeyBirt]

I am not deleting your comments, this is KZbin being overactive trying to delete spam comments. I created a post on KZbin a few days about this very subject. You can get many types of cables already made, but not all. For some applications they are unique. You can also find some replacement connectors, but not all. Some FFC connectors, like this T102 uses seem to be impossible to match to anything currently available.

[@scottmcdonnell7559]

@@HeyBirt Thank you for responding and explaining, Jeff.

[@HeyBirt]

@@scottmcdonnell7559 NP. I realize it is annoying to post a comment and have it disappear. This is happening to all content creators it seems and it does not seem like YT is trying to fix it.

[@nathanjohnson9715]

Hi Scott, any way you can help me find a 2.54mm (.1") pitch ffc? I need a couple for my trs-80 model 3.

[@dboboc]

You should take longer to get to the point.