diff --git a/source/CPU.cpp b/source/CPU.cpp
index b2d525be..c9c32e88 100644
--- a/source/CPU.cpp
+++ b/source/CPU.cpp
@@ -444,7 +444,7 @@ static __forceinline void CheckInterruptSources(ULONG uExecutedCycles)
 	if (g_nIrqCheckTimeout < 0)
 	{
 		MB_UpdateCycles(uExecutedCycles);
-		sg_Mouse.SetVBlank(VideoGetVbl(uExecutedCycles));
+		sg_Mouse.SetVBlank( !VideoGetVblBar(uExecutedCycles) );
 		g_nIrqCheckTimeout = IRQ_CHECK_TIMEOUT;
 	}
 }
diff --git a/source/NTSC.cpp b/source/NTSC.cpp
index 4793766f..ed4e33f5 100644
--- a/source/NTSC.cpp
+++ b/source/NTSC.cpp
@@ -1751,10 +1751,12 @@ void NTSC_VideoInitChroma()
 }
 
 //===========================================================================
-bool NTSC_VideoIsVbl ()
-{
-	return (g_nVideoClockVert >= VIDEO_SCANNER_Y_DISPLAY) && (g_nVideoClockVert < VIDEO_SCANNER_MAX_VERT);
-}
+
+// NB. NTSC video-scanner doesn't get updated during full-speed, so video-dependent code can hang
+//bool NTSC_VideoIsVbl ()
+//{
+//	return (g_nVideoClockVert >= VIDEO_SCANNER_Y_DISPLAY) && (g_nVideoClockVert < VIDEO_SCANNER_MAX_VERT);
+//}
 
 //===========================================================================
 
diff --git a/source/NTSC.h b/source/NTSC.h
index 886197d7..d652b67b 100644
--- a/source/NTSC.h
+++ b/source/NTSC.h
@@ -16,7 +16,6 @@
 	extern void     NTSC_VideoReinitialize( DWORD cyclesThisFrame );
 	extern void     NTSC_VideoInitAppleType();
 	extern void     NTSC_VideoInitChroma();
-	extern bool     NTSC_VideoIsVbl();
 	extern void     NTSC_VideoUpdateCycles( long cycles6502 );
 	extern void     NTSC_VideoRedrawWholeScreen( void );
 	extern bool     NTSC_GetColorBurst( void );
diff --git a/source/Video.cpp b/source/Video.cpp
index af01d673..2d66095f 100644
--- a/source/Video.cpp
+++ b/source/Video.cpp
@@ -883,10 +883,10 @@ BYTE VideoCheckMode (WORD, WORD address, BYTE, BYTE, ULONG uExecutedCycles)
 
 BYTE VideoCheckVbl ( ULONG uExecutedCycles )
 {
-	bool bVblBar = VideoGetVbl(uExecutedCycles);
+	bool bVblBar = VideoGetVblBar(uExecutedCycles);
 	// NTSC: It is tempting to replace with
-	//     bool bVblBar = NTSC_VideoIsVbl();
-	// But this breaks "ANSI STORY" intro center fade
+	//     bool bVblBar = !NTSC_VideoIsVbl();
+	// But during full-speed, the NTSC video-scanner is not updated, so video-dependent code can hang
 
 	BYTE r = KeybGetKeycode();
 	return (r & ~0x80) | (bVblBar ? 0x80 : 0);
@@ -1550,7 +1550,7 @@ WORD VideoGetScannerAddress(bool* pbVblBar_OUT, const DWORD uExecutedCycles)
 //===========================================================================
 
 // Derived from VideoGetScannerAddress()
-bool VideoGetVbl(const DWORD uExecutedCycles)
+bool VideoGetVblBar(const DWORD uExecutedCycles)
 {
     // get video scanner position
     //
diff --git a/source/Video.h b/source/Video.h
index b7d00a34..275e4145 100644
--- a/source/Video.h
+++ b/source/Video.h
@@ -176,7 +176,7 @@ void    VideoRefreshScreen (uint32_t uRedrawWholeScreenVideoMode = 0, bool bRedr
 void    VideoReinitialize ();
 void    VideoResetState ();
 WORD    VideoGetScannerAddress(bool* pbVblBar_OUT, const DWORD uExecutedCycles);
-bool    VideoGetVbl(DWORD uExecutedCycles);
+bool    VideoGetVblBar(DWORD uExecutedCycles);
 
 bool    VideoGetSW80COL(void);
 bool    VideoGetSWDHIRES(void);