Radio Shack Maximus Keyboard - Manual (Page 9)

One or several keys could have been damaged which is why you can not
turn on the keyboard. Try removing the keys one by one checking each time
whether the keyboard works. the damaged keys need replacing.
I spilt coffee/tea/water/alcohol/etc. on the keyboard
Quickly turn off the keyboard, remove all the keys or at least the keys from
the wet part. Carefully dry the keyboard and do not turn it on for a few days
as it may cause damage if there is still liquid left inside.
When the keyboard is completely dry turn it on with several keys. If it works,
install more keys having turned it off to do so. Keep installing the keys by parts
up to the last one. Even if the keyboard works, the pressing of the keys may
be impaired.