Fixing partially broken flex cable on a Thinkpad keyboard?

[zoltan87]

I have been sorting through my Thinkpad collection, and while I was at it I checked out some of the boards and parts, that I got in half-working/non-working conditions. Unfortunately in the process of swapping out multiple boards, somehow I managed to destroy a Thinkpad T60 keyboard: I must have pulled on the flex cable that goes into the motherboard too hard, as I can see the cable is partially broken now, with multiple traces not making connection any more. It's just a few millimeters after the connector. I have a feeling that the flex cable was already somewhat damaged from previous handling, I just wish I paid more attention. I was simply not expecting an issue like this, I have disassembled Thinkpads probably 20+ times by now, but this problem is completely new to me.

It's especially annoying, as the keyboard has hardly seen any use, judging from the condition of its keycaps. I saw two screws on the bottom of the keyboard, where the cable goes into it, and hoping I could simply pull the cable out I removed the two screws, but even after removing them nothing really came apart. The cable seems to be sort of sandwitched in between the metal back plate, and the front side of the keyboard. So I didn't investigate further that route.

Is it possible to somehow remove the cable, and just replace it with one from an other (same type) keyboard?

I also watched some Youtube videos about soldering broken flex cables together. Honestly it seems like an impossible task without a microscope. And even with that, I wouldn't count on my abilities to work on such a microscopic scale.

Has anyone come across this issue, and what was his/her solution, if any? If it was a worn down keyboard, it wouldn't bother me much, but as i mentioned, it's in such nice shape, I just don't want to throw it away like this. Well, I suppose in worst case scenario, I could still use the keycaps on it at least, but I am hoping there is actually a solution to bring it back to life.

[kfzhu1229]

It's especially annoying, as the keyboard has hardly seen any use, judging from the condition of its keycaps. I saw two screws on the bottom of the keyboard, where the cable goes into it, and hoping I could simply pull the cable out I removed the two screws, but even after removing them nothing really came apart. The cable seems to be sort of sandwitched in between the metal back plate, and the front side of the keyboard. So I didn't investigate further that route.

Is it possible to somehow remove the cable, and just replace it with one from an other (same type) keyboard?

When I was tearing apart not one, not two but like 4 X220/T420/T520 keyboards, I found the exact same thing on that keyboard. The ribbon cable on my T61 widescreen keyboard seems similar to that T520 one.
And if the T520 keyboard are any similar to the T60 one, the cable is indeed sandwiched between two metal plates and one side has a piece of foam on it. But actually inside the two metal plates there's also the two sides of membrane and the whole point for this sandwich is to make connection from the membrane to the cable!
So yes if this keyboard is similar enough to the T520 one, in the case of T520 keyboards the cable easily comes apart. But be advised the trackpoint comes out with the cable and there are two hidden screws, one underneath each of G and H keys.
And if it really is similar, remove the two screws securing on the bracket, as well as two screws under the G and H keys.
Remove trackpoint cap, then the trackpoint board
Then remove all tape holding the cable down to free up the cable.
Now, lifting up the metal plates the keyboard ribbon should wiggle out of there.
This is how I fixed one of my broken T520 keyboard (received for free) that has the trackpoint plastic stick snapped clean off (plus some minor liquid damage that I fixed)!
To replace the ribbon cable itself, maybe ask around on this forum to see if anyone has any T6x (and maybe even T400/T500) keyboard that's liquid damaged and keys don't work. Most likely the ribbon cable is all good as this plastic ribbon cable has wires permanently glued into the plastics so that cable is waterproof.

EDIT: as for the ribbon cable failure itself, as the T6x connector is similar to the T520 one that I am working with, this tiny connector Lenovo used is like directly onto the thin ribbon cable that is the strength of kapton tape. I've had one cable ripped right inbetween the pull tab and the connector itself but again I still have 3 of these keyboards all dead so one broken isn't a big deal at all.

[zoltan87]

I will give that disassembly a try then in the future (might will wait until a really worn down keyboard comes into my possession in one of those machine I habitually buy from time to time). Hopefully I can rescue it.

As a side-note, I was comparing my spare keyboards to each other, and it's amazing how much more flexible the T400/T500 series keyboards' backplates are compared to the T60/T61 series ones. I am not sure if it's all due to those small drilled out extra holes, or the actual backplate is slightly thinner too, but it's a huge difference. I wonder how noticeable it would be while typing on them, properly installed in a machine. It's great to save weight in portable devices, but sometimes it's just not worth it to go into such extremes.

[kfzhu1229]

As a side-note, I was comparing my spare keyboards to each other, and it's amazing how much more flexible the T400/T500 series keyboards' backplates are compared to the T60/T61 series ones. I am not sure if it's all due to those small drilled out extra holes, or the actual backplate is slightly thinner too, but it's a huge difference. I wonder how noticeable it would be while typing on them, properly installed in a machine. It's great to save weight in portable devices, but sometimes it's just not worth it to go into such extremes.

Well you have not tried the T530/X230/T430 keyboards, or even worse, the T430u's keyboard.
While those keyboards are certainly leagues and bounds better than the "touchscreen like" Macbook keyboards, they have pretty disappointing amount of key travel, and the one on my T530 is bad enough that the Latitude keyboards have to take the crown as far as comfortness is concerned.
The T430u's keyboard is even worse on top of that that if you hold down the ` key, it will catch the fan underneath and you might even burn the fan fuse just like that!

I will give that disassembly a try then in the future (might will wait until a really worn down keyboard comes into my possession in one of those machine I habitually buy from time to time). Hopefully I can rescue it.

If the keyboard you receive is just simply worn but actually fully works (or if it's missing a few keys), I think you can also swap the key, keycaps over instead of fiddling with the ribbon cable if it's only about the dozen most commonly used keys that get worn.
In order to release the trackpoint assembly, the G and H keycaps need to come off anyway.