I have a feeling it might be a solder joint under the middle relay. Heard of a few people having problem with the target dropping and also inconsistent spinning of the death star which were related to this replay having cracked or dry joints. Going to look at this today and see if it solves the problem.

On a separate note I wondering if I could draw on peoples knowledge of the game. At the end of the game what's the go with the jawas and R2D2? Thought it was just if your number matched theirs something would happen but had this happen and nothing??