reconditioning notebook keyboards?

I have a Vaio notebook on which the left shift key has suddenly intermittently stopped working. I suppose the keyboard itself is relatively easy to take it out

Does anyone know whether there is a procedure for repairing these or cleaning the contact under the key which is obviously at fault? Are notebook keyboards sealed units?

I ask because I have seen 'reconditioned' Vaio keyboards occasionally on offer. I have tried deep-spraying Magneeto tape head cleaner all over the affected area (with the key in place)to no great effect AND I have heard reports from other Vaio users that their keyboards have failed (repeatedly) in the same way, with first one key going and then a lot of its surrounding keys as well.

I can't speak about that particular model, but laptop keyboards, like most these days, consist of two layers of clear plastic with printed conductive tracks and contacts. Sometimes this may be one assembly (bonded together?) and cannot be seperated. Keyboards are often held together by dozens of tiny screws. Sometimes they are unfortunately held together by dozens of melted over plastic pins for quick and easy assembly, making reassembly a challenge.

It's not hard to open up keyboards, and once open the fault can easily be found with a multimeter. I'd look for a broken trace next to the affected key, and if you find one, repair it with rear car window demister repair paint- available at car accessory shops. A thin coat is ideal, don't pile it on, and allow it to dry thoroughly. Overnight at least to make sure it's completely cured.

Failing that, clean the contacts with isopropyl alcohol or meths, allow to dry thoroughly and reassemble. You may as well clean all the contacts when you do this. In fact- I'd recommend you do this anyway, spraying head cleaner on the keyboard was unwise and it may as well be cleaned properly while it's dismantled. It's also possible the contact has worn out, you may be able to repair this with the same conductive paint I mentioned, but don't expect it to last.

Incidentally- spraying cleaner into a modern laptop keyboard will not clean the contacts, it won't get anywhere near the contacts in fact. What it could do is seep into the laptop's electronics and destroy it.

Dave