I did this and it worked for me, where everything else failed.

Tool - sharp and small metal "spike" that dentists use to dig your teeth,
yea, you know what I mean ;-)

On motherboard, under the keyboard is the connector for the keyboard and I
worked on the half that is attached to the motherboard.
If you look with a magnifying glass you'll see that the connector has small
pins on the sides and that the cable connector goes in between these pins.
Also you'll see how these pins are attached to the plastic body.
I pushed GENTLY this steel pin between the plastic body and the pin and this
bends the pin slightly inwards, so that when you plug in the keyboard, the
pins press harder against the plug.
Repeat this process on all pins on both sides of the connector, and you are
done!

This worked for me.

Jan