Pads playing wrong samples cutting off and stuttering, is sh

Whats up. It's Bond, from Backwoodsz Studioz Brooklyn NY. First post on this forum, been reading it for a while.

Got an issue with with pads 1,5,9 and 13. They play the assigned sample then glitch and trigger another sample. Then it stutters, with two samples playing like I'm holding the note repeat. Turn the mpc off and back on and it goes away for a bit, then comes back. Doesn't happen to the samples if I use an external midi keyboard.
Running the free JJOS, and it's a 2500 maybe 4 years old. I have switched some buttons and the rotary wheel on it.
I'm thinking it's starting to die on me. But I did take it apart and clean the sensors, and reinstalled the operating system. Maybe it's a weird midi issue, but it's just happening on the four pads on the left.
Anyone out there got an idea of what's going on?

i used to know a guy called the black bond in worcester... i still cringe when i think about him.

http://www.theblackbond.com/direction.php

if it doesn´t happen if you are playing on a midi keyboard, i assume you need new pad sensors.

Thanks. When you said Worcester I was thinking Massachusetts but the accent put me wise.