A couple of thoughts: I have left my TT-101 powered up continuously for months now. I start it spinning when I want to play. No apparent ill effects and no problems with power supply glitches that were starting to appear before I adopted this approach.
I concur with the suggestions to Lew that the motor height is off slightly leading to the scraping sounds. Both suggested solutions: checking the screws that hold the motor cover in place - they use two different metal washers, stacked,and adjusting the bearing cap are the right ones. I would also add that the motor itself is screwed down onto two thin washers (that I replaced with rubber/steel)
Inside the bearing cap is a white nylon or similar thrust pad that on mine has an indentation where the ball sits. I wanted to take it out and replace it with Lignum Vitae but was unable to remove it without causing damage so left it alone.
I believe that the indentation in the thrust pad is original but have no evidence for that - it could have been worn into it by the years of rotation. I tend to believe that the ball is held by the end of the spindle (it is cupped) and rotates on the thrust pad which because of the indentation has a rather large contact area with the ball. To my thinking this creates a large area that needs lubrication and it is critical that the lubricant is not squeezed out leaving a dry center - so I used a 5w-20 Mobil one that I have on hand. Next time I take it apart I will switch to an even lighter synthetic (0w-5 Redline Racing).
The ball I put in is Si3N4 (Silicon Nitride)and it is 4.06mm in diameter (even though I bought it at 4.0mm and the original steel ball is 4.01 mm it all seems fine).
I concur with the suggestions to Lew that the motor height is off slightly leading to the scraping sounds. Both suggested solutions: checking the screws that hold the motor cover in place - they use two different metal washers, stacked,and adjusting the bearing cap are the right ones. I would also add that the motor itself is screwed down onto two thin washers (that I replaced with rubber/steel)
Inside the bearing cap is a white nylon or similar thrust pad that on mine has an indentation where the ball sits. I wanted to take it out and replace it with Lignum Vitae but was unable to remove it without causing damage so left it alone.
I believe that the indentation in the thrust pad is original but have no evidence for that - it could have been worn into it by the years of rotation. I tend to believe that the ball is held by the end of the spindle (it is cupped) and rotates on the thrust pad which because of the indentation has a rather large contact area with the ball. To my thinking this creates a large area that needs lubrication and it is critical that the lubricant is not squeezed out leaving a dry center - so I used a 5w-20 Mobil one that I have on hand. Next time I take it apart I will switch to an even lighter synthetic (0w-5 Redline Racing).
The ball I put in is Si3N4 (Silicon Nitride)and it is 4.06mm in diameter (even though I bought it at 4.0mm and the original steel ball is 4.01 mm it all seems fine).