The keyboard is acting up on my Wifey’s precious TR3.  The decimal key must be pushed extra hard, till you feel a definite ‘click’ to get it to register.  The S key is also a bit flaky, but not so bad. 

I wish to investigate further…do the keys just ‘pop’ off? 
Is it possible that something is lodged under a key? 
Is keyboard failure a good probability? 
I fix everything myself (electronics background), but have never cracked open a laptop.  Is it scary-difficult?

Yes, you can easily pop off the keys.

OK, that was easy…one of the ‘hinges’ came loose…I put both hinges under their rubber flaps, and snapped the key back on.  Works great. 
Thanks.