This unit advances by three positions correctly from the zero position and with three balls per game selected. However, nothing happens after that with either 3 or 5 balls per game selected. The holes lite up randomly, one at a time, but when a ball is dropped into that lit hole, the arrow unit still does not advance. The schematic makes no sense to me as the triggering relay (V) should advance the arrow unit as a result of the ball dropping into the lit outhole. As per the schematic, no advance can occur as there is a Normally Open contact on V preventing that signal from the outhole from activating the V relay again. Is it possible that there is a mistake on the schematic? Any thought would be appreciated.