midi channel recording problem

[chuckeys123]

Hey guys. I'm trying to add a track to an existing midi file. I load the file, leave one open channel on record, the rest on on. I start record, and the tempo  doubles in speed. What could I be doing wrong, and is there a good information source about making changes in a file? Maybe I missed it, but I found little help in the manual or reference manual..(I have the psr s770). Thanks