Hi Calton Clocks may help they have they have parts including contacts,Peter Smith of Horlogix retired some time ago, new contacts should have a diode , fitted to stop the contact sparking and burning I used 1s113 diode case do7 from ,The Little Diode( Company) with good effect,Dave West at Honington Bury St Edmunds, repaired one of my Eurekas some time ago, there are lots of mythes around these clock there probable dozens of variations in the cases possible because the movements were sold on, and various firms companies put the movements in their own cases, but the movements are just two types tall and short, but there are some more rarer three ball bearing as opposed to the usual two, in all the time I have been interested in Eureka Clocks I have only seen one other type. I am given to believe that around 10 thousand were made in a relative short while, prior WW1, but judging buy the amount that have survived I find it hard to believe, the bearings gum up I have found it quite easy to remove the ball bearings and clean them even move the outer race if worn, and re oil, don't be frighten to oil don't flood it but make sure there is enough, i wouldn't take much notice of serial numbers one of mine has no numbers on it either, they seem to bear little relationship of when to was made.
Terry Gray