mpc 2500 track drop outs Please help!!!!!!

i have an issue with my mpc 2500 I just purchased it 3 months ago. when i am recording tracks to create a sequence certain tracks drop out during playback. I went to the store where i purchased the Mpc and no one has ever seen anything like this before. They say im doing everything properly but no one can seem to figure it out. i have been recording samples into the mpc and the first 3 or 4 tracks do fine after that tracks start to drop out. Please help I never use the track mute feature so thats not the problem.Please help!!!! Somebody anybody!!!!

It's possible that you could be maxing out the polyphony...
might not be the problem, but it's a good starting point to trouble shooting it.
What happens when you record the note data on one of the already used tracks?