Recording problem

Hi, I'm new to the list and new user of mpc 2000 xl (just got it last friday).

So anyway I have this problem when recording a sample. When I switch my mpc on and sample a sound from a record it works just fine at first, but when I try it again or try to sample another sound, left channel is missing or it sounds very low or distorted. I tried deleting all sounds and doing it again but that doesn't help so it's not a memoryprob' . Only way to get it work is to switch off and restart, and that cant be the right way. I've tested other jacks and it still does that so it's the mpc. So, is my mpc just busted or am i missing something?

Thanks
Tomi

does your turntable go through a phono preamp?..

It goes through numark mixer (for amp) to a line mixer (so that both channels have their own line and a lil' pre eq) and then to mpc.

Wait, I think I got it, the signal was too weak..me thinks, now it sounds ok.
Thank yous.