Mr Leckmeck beat me to it.
The axle for the reset bar has the spring on the ends. The smaller target banks that only use 1 reset solenoid "might" only have the torsion spring on one end. Pictured below is one of the springs from an Atlantis 10-target bank. The Gottlieb part number for the spring appears to be A-13455. If your target banks have the spring(s) intact, then the pivot points (and solenoid coil sleeves?) might be gunked up and sticking.