Weird pitch control problem.

I'm using an Audio 6 w/ 2 technic 1200 mk2s and a stanton m203 mixer. I recently just got my audio 6 package off ebay, and i had a store repair these technic i got for cheap. I'm having a weird problem whenever I try to change the pitch of a song it will bounce from pitches dramatically and my bpms constantly bounce it will change from 128.00 to 127.97 without touching the pitch control. My main problem is the fact that my pitch control is off, For Example on both turntables when I try to move the pitch to a higher percentage from +0-2% it lowers for some reason.. if i'm playing a 128 bpm track it will lower to 126 in between those 2 percentages, but when I past the 2% mark it goes back to original bpm and seems to be normal from there when adjusting pitch or as normal as can be. Same weirdness for when I try to decrease the pitch its really sensitive, when I move the pitch even to the first line it will bounce from 128 to 124 and won't even get to the 2% mark when lowering pitch. Basically the main problem is that my pitch control is off, not accurate and jumpy. Anyone know what could be the source of this problem? Maybe it could be the tables since they were second hand. It's really irritating as it is a pain to beatmatch. I will give more info if needed just sorta broke it down here. Thanks for any help!