Anything I should know before buying a Micro Seiki RX-5000

Sure you want to do that???   Lot of money for a 40 year old turntable from a defunct brand...

oddiofyl + 

While I don’t disagree with the above sentiment, you are likely to find more Micro S ownership joys and pitfalls both real and imagined dragons on the WBF site.

while I do happen to own two ancient Denon from the era, my unsolicited advice is buy a Brinkmann Bardo…

Those two MS TTs will be working up to spec when most of us have turned to dust, and beyond. There are two elements that will need attention over time: the belt and the motor, same as any brand new belt drive TT. Check for bearing wear as well but otherwise they consist of two solid chunks of metal that ain’t going anywhere and there are modern motor systems that could replace the original.