Pitch wobble 1210

Hey i have had problems with pitch accuracy on a technics1210 mk2 for months and recently have replaced the pitch controller with a second hand pitch controller (the old one was proper knackered anyway), i have been assured that it was checked for integrity. the problem has become less acute since the swap but is still not 100% fixed. the problem is this, when moving the pitch slider through its range in certain places the speed of the platter revolution fluctuates causing sound to fluctuate simultaneously. i know your first answer will be to try a brand new pitch controller, and i will eventually, but for know i need to know what else i can do to try and improve/fix this fault. also the led on the new pitch controller doesn't work and this was also the case with the old pitch, could this be linked in some way to my current problem im wondering if my overall problem could be caused by faulty circuitry....
any info will be greatly appreciated
many thanks
dean