Reset the thing once more. It sounds like its in its receive mode but a reset
(either chord I or chord "for" should fix that. If it doesn't you may have a
problem.
What you might try doing to stop it is to hit a chord z and see if that will
terminate it for you.
Tom
Tom Brennan KD5VIJ, CCC-A/SLP
web page http://titan.sfasu.edu/~g_brennantg/sonicpage.html