Are you sure it was the castle VUK and not the Winkie? There is a switch at the bottom of the Winkie that let's the OS know it's down. If it doesn't know where the Winkie is it will keep firing the Winkie coil. You will see a protrusion near the bottom of the Winkie that engages the leaf spring looking thing that protrudes from the little black box with the switch in it. Make sure the leaf actuator is on the correct side of the protrusion and also the switch is working properly - you should here it click when Winkie goes down. Pin should be off when doing the above.

Check in switch test mode for proper Castle VUK operation. You can take a piece of paper and insert in VUK hole which should turn the test mode light from green to red (or vice versa).

If test mode of VUK shows nothing is working something is unplugged so you'll have to trace it back