Need to adjust the speed every time I turn on turntable


Need to adjust the speed every time I turn on turntable.This is a belt driven Oracle Delphi II with Origin Live motor and Origin Live Control Board and Origin Live Power Supply.  I am guessing it can be the belt, motor, control board and /or power supply.   How do I determine what is not working?
dcaudio
Just wanted to point out that many of the posts seem to confuse long term speed stability with instantaneous speed stability.  A turntable may measure out perfectly for speed over longer time intervals yet still create momentary episodes of pitch instability due to short interval speed errors.  There's a difference.
A dirty belt/belt tension is the number one cause of this in my experience, also check to make sure pulley isnt slipping on motor shaft and be sure to clean pulley grooves

Bruce 
I have been in contact with Origin Live this week.  When they saw the pictures from my setup they said motor and transformer is 15 years old.  Must buy new both control board and transformer.  When I said - has only been used 200 hours.  Do you provide any discount for existing customer they said - read our FAQ.  It must be something else.Any thoughts????
15 years old and only 200 hours.... the filter caps in the power supply could easily be defective as a result (they last longer when charged). It may be that the regulators are unable to regulate the DC voltage as a result.