Electra Super Deluxe 1200: Programme running very slow with delays?

When I set my washer up it starts the cycle ok then comes to a complete stop part way through. At first I thought it was the programmer that had just gone wrong but then I found out that if I leave the machine alone it will start again after several hours and cary on with the next part of the cycle. This happens twice during one wash cycle so it takes a really long time to get the washing through but I have no idea what the fault could be. Can anyone offer any suggestions? Many thanks in advance
Jan