Sounds like it has a vibrato micro seiki dd 25

Hi, first thing you need to do is check your strobe lights , if you look near your power on/off you should notice a little guide with +6 0 -3.33 etc, set your pitch to 0 for instanceand watch the platter by the light on the on off switch, the big dots on the plater should stay stationary whilst the smaller dots above it and below it move around it, if the big dots don't stay still it may well be a problem with your pitch control,, these arent too hard to replace and arent that expensive
http://www.youtube.com/watch?v=PRE6LvWrhbs
Is difficult for me to say without looking at them
But if it seems like your decks are holding pitch then it might be somthing more complicated and you might need to take it to your local technics repair centre, you can find this by typing in the name of your town / city and technics service/repair
Bare in mind that you can get a kind of warble when you leave the pitch fader really close to zero but not quite on zero and it wil flicker between 0 and +1
A useful resource is http://www.turntabletech.com/ have done a few services myself of info off this site
last thing dont get ripped off by the service centre, i.e paying £300 to repair a technics probs aint worth it when you could buy a refurb one for less.
Good luck