What causes irregular spin cycle to the Zanussi, Nexus, FL884 washers?

I have an old model Zanussi washer. It has performed brilliantly over the years, but recently it has started to malfunction during the spin cycle. Sometimes it spins, and other times it dosent. It has been serviced regularly, and so the performance is baffling. It has been cared for like a child.
It spins without a load right on mark, but gets moody when it has loads. My technician is trying to get the wiring diagram for the machine, can you assist? Will this advice cost me?