I purchased this Vienna Regulator clock in 1970 while stationed in Germany from a friend who was an American antiques dealer living there. I know nothing of its history or who made it (haven't taken the movement out of the case yet). The movement has a hallmark of just two crossed arrows. I just want a notion of what it might be worth and perhaps if it is worth fixing. The mainspring broke after about 1979 and has not been repaired.