The motor shaft should spin freely. As musicmm said the bottom bearing may be gummed up.
The approach Which I would take is to grind off the peened spots retaining the bottom plate with the plan of securing the plate with J&B weld after the cleaning and lubing is complete.
Remove the bottom plate then push the rotor out by pressing on the top shaft. Keep track of all the thrust washers which you may find so they can be returned to their original position.
After the rotor is removed clean both the top and bottom bearings and any oil wicks with throttle body cleaner. After they dry saturate the wicks with sewing machine oil and reassemble the motor. Clean the surfaces where you are to apply the J&B weld. Retain the bottom cover with a couple of C-clamps. Verify that the rotor spins freely then apply the J&B weld and allow to cure.
There is a capacitor on the power supply board (C1) which is the motor run phase capacitor. If freeing up the motor doesn't restore operation verify that the capacitor is good. If it is shorted the motor will not run.
If all else fails you might contact these folks for a replacement motor: http://organdonorparts.com/Pioneer_c13.htm
If they have a motor for a decent price fine, but if it gets north of ~ $100 I would recommend considering a DC conversion from these folks: http://www.esotericsound.com/index2.htm
An AC hysteresis synchronous motor is a fine quiet motor and has speed accuracy, however with a high speed motor such as you have the belt is critical to platter speed accuracy.
When the manufacturers were supporting these machines this was no problem. Now getting the correct belt is often a real hassle. The servo controlled DC motor offers adjustable speed so any flat belt of the correct length will be suitable.
Hope my thoughts are useful.
Captgogo wrote:So from this photo getting access to the bottom bearing does not seem to obvious to me.