The tilt sensor was designed so that when you tilt the LCD screen towards you it will activate. My 890 activates exactly as it was designed. It turns on at an angle less than 45 degrees from horizontal. If you have to tilt the LCD screen away from your eyes then you are correct in assuming that there is a problem.
Check this post for a description on how it works.
[Link: remotecentral.com]Try a firmware upgrade on the remote before you take the thing apart.