I would try placing the platter upside down on a sheet of glass and pushing down at various points on the perimeter. If you get a buzz or increased buzz at s point or two, then the platter is warped. If not, then it could be the spindle or user installation issue.
I have a 1200G. The brass platter is mounted by 3 brass screws. It took me 3 times to get the screws to seat perfectly into their counter sinks.
Would they have seated on their own if I just continued to tighten? Probably...but I didn't want to take a chance so I restarted 3 times until I got it right.
The point is. The turntable may be completely defective...but sometimes it's just easy to get something wrong 3 times. Try to find out what's going on. Yes, it should never be this difficult. But sometimes I've found that I've done some strange things to get things consistently wrong.
But then again I'm a special case.