Lenovo Yoga touchpad buttons not working

[Zinput]

I have a Lenovo Yoga/Ideapad 910-13ikb. It is specced with the Core i7-7500U and 8GB of RAM. The problem is that the touchpad buttons do not work anymore after the laptop was exposed to water. The touchpad tracking works, and I am able to use it with gestures, but I would like to fix the buttons. So far, I have tried reinstalling the Windows Precision Touchpad drivers, trying several different Linux distros, resetting BIOS, reseating the touchpad ribbon cable, cleaning the motherboard with an electronic contact cleaner, and replacing the touchpad. There are no signs of corrosion inside except on the fingerprint sensor, which I have replaced too. Any ideas? The only thing I am not willing to do is to replace the motherboard because it costs more than what this laptop is worth.

[mon2]

Re: Lenovo Yoga touchpad buttons not working

To which connector do the touchpad buttons mate with on the logic board ?

[Zinput]

Re: Lenovo Yoga touchpad buttons not working

The entire touchpad and its buttons are in one assembly and connect to the motherboard with a ribbon cable. There is also a strip of foil that crosses from a large copper contact on the trackpad to the chassis of the laptop. I believe there is a downloadable schematic, but I do not know how to read it.

[mon2]

Re: Lenovo Yoga touchpad buttons not working

The interconnect is a ffc (flat flexible cable).

On this note, any damage to the contacts of the fpc?

Is this cable the original? Any liquid spill on this cable or contacts? You can use ipa (alcohol from pharmacy section of Costco is great) with Q-tip to clean the contacts.

On the logic board, what are the silk screen labels for this connector for the touch pad.

The schematic had numerous connectors so want to be sure the right one is being reviewed.

[Zinput]

Re: Lenovo Yoga touchpad buttons not working

The interconnect is a ffc (flat flexible cable).

On this note, any damage to the contacts of the fpc?

Is this cable the original? Any liquid spill on this cable or contacts? You can use ipa (alcohol from pharmacy section of Costco is great) with Q-tip to clean the contacts.

On the logic board, what are the silk screen labels for this connector for the touch pad.

The schematic had numerous connectors so want to be sure the right one is being reviewed.

The contacts of the cable look untouched, golden. The contacts of the connector that the cables slot into look golden too. I am not sure if this is the original cable because I got them mixed up when I swapped the new touchpad into this laptop. There doesn't seem to be a liquid spill on the cable or the contacts, and it's unlikely since it's on the underside of the logic board and the only sign of corrosion was way over to the left on the fingerprint sensor that I replaced. The silk screen label for the touchpad connector is JP9.

I have attached some images to this link: https://imgur.com/a/6dvaNXP

[mon2]

Re: Lenovo Yoga touchpad buttons not working

The proper cable is very important and may be the root cause here.

Do this, remove all power.

Remove this cable and count the number of gold pads.

If you can, post a clear pic of the cable gold pads. Also post a clear pic of the connector where this cable is mated.

We need to verify the number of contacts on each.

The connector on the logic board will most likely be a surface mount part. That is, you should be able to see a solder contact for each cable contact.

Count the number of connector contacts.

They must match the cable contact and be at the same distance between the pads. This is called the cable or connector pitch. If the pitch is not 1:1 then the touch pad signals will be shorted. This fault does happen on the MacBook models so very important to check this.

[Zinput]

Re: Lenovo Yoga touchpad buttons not working

The proper cable is very important and may be the root cause here.

Do this, remove all power.

Remove this cable and count the number of gold pads.

If you can, post a clear pic of the cable gold pads. Also post a clear pic of the connector where this cable is mated.

We need to verify the number of contacts on each.

The connector on the logic board will most likely be a surface mount part. That is, you should be able to see a solder contact for each cable contact.

Count the number of connector contacts.

They must match the cable contact and be at the same distance between the pads. This is called the cable or connector pitch. If the pitch is not 1:1 then the touch pad signals will be shorted. This fault does happen on the MacBook models so very important to check this.

There is a picture included on the Imgur link that shows the cable and connector contacts as well as the solder joints. There are six contacts on all the parts. The cable is also labeled TP_FFC.

[Zinput]

Re: Lenovo Yoga touchpad buttons not working

Here's an update on the problem. Somehow, my trackpad is starting to work again even though I have not done anything to it. It requires a large amount of pressure and only works half of the time, but it's better than not working at all.