I had my unit serviced, it arrived and performed flawlessly for about 15 min, then began running slow. The repair shop led me to remove the platter and clean the underside of the platter and the pickup sensor. It helped 99%. I noticed the speed would skip -slow down then catch up- regularly at a spot under the platter where the black paint has been stripped. Does this have anything to do with it? How do I fix this? I don't want to repair it with generic paint. Last resource, replace the platter. Any recommendations?