I'm still trying to learn schematics so I can fix my Skateball that has some major rectifier/wiring problems.
Aux Board shows F1 is 25v as well as F2. Connector J11 & J8. They both go through BR1 (Bridge)
Maybe your B1 Bridge is bad or shorted or something.
I'm a newbie pinball tech though. Someone else could chime in and be more specific I'm sure hahaha.