I am working on a Stern Quicksilver with a locked on kick out hole solenoid (Q13 on the board). The board is STERN SDU-100. I tried putting a good Bally 2518-16 SDB in the Quicksilver in place of the SDU-100 and it went nuts. The drop targets started cycling reset, and I'm not sure what all else was cycling. There was a lot of clattering going on. I shut it down and put the SDU-100 back in and the cycling went away. I thought Bally and Stern solenoid driver boards were interchangeable. Can someone enlighten me why the Bally board didn't work in the Quicksilver? (in the meantime, I am ordering parts for the Stern board).