Before you do anything, I would suggest that you align the spindle correctly to the head, JFgoods has outlined the belt change and adjustment at http://jfgoods.net/disksystem.html
. The steps are not numbered in his article. However, the procedure starts at this slide:
"Here comes the most important part.
First, slide the head so you will get a view like shown on the left
Once you have that spindle adjusted then start adjusting the motor speed.
If you have a famicom copier, you can use a utlitiy like CopyMaster to find the speed of your drive. If you don't have the famicom copier/copymaster setup, you have to manually adjust the speed (in small increments).
As I mentioned before, the motor has a +/- sign etched into the motor. You can use a slotted screw drive to make the adjustment. Use the screw driver to turn motor adjustment screw clockwise or counter clockwise. The direction corresponds to the speed. You have to do trial and error in terms of adjusting the motor speed.
What this means is that you have to adjust the speed, then load a game. Keep trying this till the game loads correctly. If the game loads then try another game. Once you are satisfied this works for all games, then you have the proper speed.
Usually in Hong Kong, technicians adjust the speed to 5 for optimum speed. But the important thing here is for the game to load.
Only adjust the head as a last resort.