diff --git a/src/mame/drivers/bfm_sc2.c b/src/mame/drivers/bfm_sc2.c
index d9d4ca14985..94436f9f017 100644
--- a/src/mame/drivers/bfm_sc2.c
+++ b/src/mame/drivers/bfm_sc2.c
@@ -199,7 +199,7 @@ public:
 	optional_device<stepper_device> m_reel3;
 	optional_device<stepper_device> m_reel4;
 	optional_device<stepper_device> m_reel5;
-	optional_device<upd7759_device> m_upd7759;
+	required_device<upd7759_device> m_upd7759;
 	optional_device<bfm_bd1_t> m_vfd0;
 	optional_device<bfm_bd1_t> m_vfd1;
 	optional_device<bfmdm01_device> m_dm01;