how do i fix it?

30 year old model? Bet you never do a hot wash at all. These machines were often not spinning due to soap crud build up on the brass bearing that it rotates on. Fill the machine with really hot water, even add a jug or two of boiling water. Let it agitate for a few minutes. Stop machine & gently rock inner bowl backward & forward and also side to side a few times. Then turn it back on and let it agitate for about 10 minutes then put it on spin.

Lincoln Appliance NZ
May 2012