To check for bad bearings, balance the tonearm and move the tonearm towards the plater spindle, the anti-skating should move the tonearm back to the rest post. Start near zero and increase the anti-skating if it fails to return, the lower the value the better the bearings as long there is no radial and axial play or slop in the tonearm bearing assembly.
Also verify that the cueing arm that lifts the tonearm is fully retracted prior to the above test.
Also verify that the cueing arm that lifts the tonearm is fully retracted prior to the above test.