Thanks for the replies, I finally have a spark, found slivers of iron on the pulse generator shorting out the wires. The magnet in it attracted the iron and shorted out the wires. Still have to work out where the slivers came from, they are definately steel not white metal but have been under extreme pressure, all curved. Haven't started it yet, have to wait for gaskets, one of the problems of living in  a remote town.

                                                                            Imi.