Help with fixing a rubber dome board (Probably the controller)

[Jimi14]

(Not sure if this is the right place to post stuff like this)

So here is the deal, some time ago i had a bit of an drink incident with my SUH 105DA (The best rubber dome i ever found, hence why i don't want to throw it away). But after i cleaned everything let it dry though, i found out that something must have gone wrong, as a bunch of keys would no longer register.



Diagnosing the problem (i'e, testing the lanes) i found out that it was the two 'outer' ones who was responsible for all these keys, but no matter how much i tried i couldn't find anything wrong with the lanes themselves, as there seemed to be no blockage anywhere.

So naturally my attention turned to the controller and and whether it might not have proper contact with the board. Doing some more testing though i still couldn't find any issues, it definitely had contact as the ones giving me trouble still worked if i installed the controller the wrong way (Obviously registring the wrong keys though). So now i have no idea what the issue can be.

Can anyone give me some advice? like i said, i don't want to throw the board away since i'm never gonna find another.



(It's the two contacts on the right that's giving me issues)



(On the controller in would be the two on the left )

[swampangel]

So naturally my attention turned to the controller and and whether it might not have proper contact with the board. Doing some more testing though i still couldn't find any issues, it definitely had contact as the ones giving me trouble still worked if i installed the controller the wrong way (Obviously registring the wrong keys though). So now i have no idea what the issue can be.

When you installed the controller backwards, did _all_ the keys work, or were there still 2 rows' worth of keys that didn't work, just elsewhere on the board?

Can you put a bit of foam in there somewhere to apply extra pressure to the connector when reassembled? Probably either on the top side of the controller, or under the curved end of the membrane in your photo.

If you have a multimeter, check that the 2 problem contacts on the controller board still have continuity to their connected solder pads, and that the solder is still connected to the leg of the chip on the other side of the board. If you have a problem caused by corrosion, this is hopefully where you will find it.

[Jimi14]

So naturally my attention turned to the controller and and whether it might not have proper contact with the board. Doing some more testing though i still couldn't find any issues, it definitely had contact as the ones giving me trouble still worked if i installed the controller the wrong way (Obviously registring the wrong keys though). So now i have no idea what the issue can be.

When you installed the controller backwards, did _all_ the keys work, or were there still 2 rows' worth of keys that didn't work, just elsewhere on the board?

Can you put a bit of foam in there somewhere to apply extra pressure to the connector when reassembled? Probably either on the top side of the controller, or under the curved end of the membrane in your photo.

If you have a multimeter, check that the 2 problem contacts on the controller board still have continuity to their connected solder pads, and that the solder is still connected to the leg of the chip on the other side of the board. If you have a problem caused by corrosion, this is hopefully where you will find it.

Iv'e done some further testing now since i posted, and i think the later scenario you suggested now might actually be the issue.

The contact on the far left on the controller do actually seemed to have lost i'ts connection to the chip, or at least i can't seem to able to get a signal between it and the leg its supposed to be connected to with a multi meter. (I do with every other contact, as well as with i'ts soldering point on this side of the controller)

Not sure how i would be able to test this theory though without bypassing the connection entirely with a wire.

[swampangel]

Not sure how i would be able to test this theory though without bypassing the connection entirely with a wire.

As a first attempt, you could just reflow the solder attached to that pin, in case it's just a flaky/marginal connection.

I don't know what material the contact pads would be made of, so I wouldn't know how to begin fixing or replacing one. Hopefully some of the greater minds here will arrive with suggestions

[Jimi14]

Not sure how i would be able to test this theory though without bypassing the connection entirely with a wire.

As a first attempt, you could just reflow the solder attached to that pin, in case it's just a flaky/marginal connection.

Could try. Don't have access to a heat gun right now though, and i doubt a hair dryer will be enough.