It sounds like the game does not know that there are two balls in it. Can you remove the apron and confirm that both trough switches work in switch test mode? (You don’t really need Leon’s test rom once the game is booting.). While in there, make certain there are no physical problems clogging things up. Both balls should be in the trough, one should NOT be in the out hole.
Another common issue is the start button may not be registering. Confirm it works in switch test as well. Also check the out hole switch is registering every time.
It’s also worth mentioning that it is also
Important to check there are no EXTRA switches closing that should not be, while in switch test. It’s so important and a lot of people do not realize this.
I’ve owned a few Sorcerer’s and these two things were actually a problem on both!