Tricity Bendix washing machine?

My Tricity Bendix washing machine sometimes stops and the red light flashes to say its stopped working. It would appear to be when it spins. I assumed there was too much washing in originally but now it is happening more frequently even when there is little washing in. Sometimes it works and sometimes it just stops. One thing is certain I cannot put anything heavy in even a heavy T shirt or a towel. I wondered whether it could be the belt or something simple. Does anyone one have any ideas. Thanks