diff --git a/src/mame/drivers/megasys1.cpp b/src/mame/drivers/megasys1.cpp
index 530120bc831..446b4b64c1c 100644
--- a/src/mame/drivers/megasys1.cpp
+++ b/src/mame/drivers/megasys1.cpp
@@ -1501,7 +1501,7 @@ static MACHINE_CONFIG_START( system_A, megasys1_state )
 
 	/* video hardware */
 	MCFG_SCREEN_ADD("screen", RASTER)
-	MCFG_SCREEN_REFRESH_RATE(60)
+	MCFG_SCREEN_REFRESH_RATE(56.18) // same as nmk16.cpp based on YT videos.
 	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
 	MCFG_SCREEN_SIZE(32*8, 32*8)
 	MCFG_SCREEN_VISIBLE_AREA(0*8, 32*8-1, 2*8, 30*8-1)
@@ -1563,7 +1563,7 @@ static MACHINE_CONFIG_START( system_Bbl, megasys1_state )
 
 	/* video hardware */
 	MCFG_SCREEN_ADD("screen", RASTER)
-	MCFG_SCREEN_REFRESH_RATE(60)
+	MCFG_SCREEN_REFRESH_RATE(56.18) // same as nmk16.cpp based on YT videos.
 	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
 	MCFG_SCREEN_SIZE(32*8, 32*8)
 	MCFG_SCREEN_VISIBLE_AREA(0*8, 32*8-1, 2*8, 30*8-1)
@@ -1637,7 +1637,7 @@ static MACHINE_CONFIG_START( system_D, megasys1_state )
 
 	/* video hardware */
 	MCFG_SCREEN_ADD("screen", RASTER)
-	MCFG_SCREEN_REFRESH_RATE(60)
+	MCFG_SCREEN_REFRESH_RATE(56.18) // same as nmk16.cpp based on YT videos.
 	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
 	MCFG_SCREEN_SIZE(32*8, 32*8)
 	MCFG_SCREEN_VISIBLE_AREA(0*8, 32*8-1, 2*8, 30*8-1)
@@ -1691,7 +1691,7 @@ static MACHINE_CONFIG_START( system_Z, megasys1_state )
 
 	/* video hardware */
 	MCFG_SCREEN_ADD("screen", RASTER)
-	MCFG_SCREEN_REFRESH_RATE(60)
+	MCFG_SCREEN_REFRESH_RATE(56.18) // same as nmk16.cpp based on YT videos.
 	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
 	MCFG_SCREEN_SIZE(32*8, 32*8)
 	MCFG_SCREEN_VISIBLE_AREA(0*8, 32*8-1, 2*8, 30*8-1)