Intermittent Keyboard Issues with P950HR / NP8952

About 6 months ago, my wife spilled some water on her laptop keyboard which resulted in the T key intermittently not working. I replaced the keyboard which solved the problem for awhile (~4 months), but now the issues are returning and increasing in frequency. In addition to the 'T' not working most of the time, she is having increasing problems with left Ctrl, num pad 0, and sometimes others eg: 7, 8, Y, G, H, J.

I've tried disassembling the laptop and cleaning connectors with alcohol, re-seating keyboard cables, uninstalling keyboard drivers, and testing key response outside Windows. The only thing that seems to help is when the laptop is hot, like while gaming.

What confuses me is why this issue is intermittent, improved by heat, and seemingly getting worse now when any water damage occurred a long time ago. I'm starting to think it has less to do with any old water damage to the motherboard, and might just be physical wear of a flimsy keyboard. I'd appreciate any ideas on how to fix or diagnose this.

 

Check the keyboard ribbon socket for any corrosion.

 

Liquid damage can be a slow killer. Likely some got on a contact in there and started corroding/oxidizing/whatever the metal. There was still an electrical connection so it seemed fine, but now it's interfered with that. For the heat helping I am a little fuzzier but I'd guess something is expanding with the heat and pushing something else that little distance to where there's a current again. If that's the case it will stop improving things after the corrosion expands more.

 

The keyboard controller on the motherboard could have suffered some of the spill damage - as Eric said above, liquid is a slow killer with PCBs. Or, coincidentally, maybe the keyboard or keyboard controller is going out.

 

Do an inspection round the area, look closely, are there any signs of corrosion?