diff --git a/src/emucore/TIASurface.cxx b/src/emucore/TIASurface.cxx
index 74cdc2efa..17b75197d 100644
--- a/src/emucore/TIASurface.cxx
+++ b/src/emucore/TIASurface.cxx
@@ -219,9 +219,15 @@ void TIASurface::enableNTSC(bool enable)
 {
   myFilter = Filter(enable ? uInt8(myFilter) | 0x10 : uInt8(myFilter) & 0x01);
 
-  // Normal vs NTSC mode uses different source widths
-  myTiaSurface->setSrcSize(enable ? AtariNTSC::outWidth(TIAConstants::frameBufferWidth)
-      : TIAConstants::frameBufferWidth, myTIA->height());
+  uInt32 surfaceWidth = enable ?
+    AtariNTSC::outWidth(TIAConstants::frameBufferWidth) : TIAConstants::frameBufferWidth;
+
+  if (surfaceWidth != myTiaSurface->srcRect().w() || myTIA->height() != myTiaSurface->srcRect().h()) {
+    myTiaSurface->setSrcSize(surfaceWidth, myTIA->height());
+
+    myTiaSurface->invalidate();
+    myTIA->clearFrameBuffer();
+  }
 
   mySLineSurface->setSrcSize(1, 2 * myTIA->height());
 
diff --git a/src/emucore/tia/TIA.cxx b/src/emucore/tia/TIA.cxx
index f713f0586..60608b765 100644
--- a/src/emucore/tia/TIA.cxx
+++ b/src/emucore/tia/TIA.cxx
@@ -899,6 +899,13 @@ void TIA::renderToFrameBuffer()
   myFrameBufferScanlines = myFrontBufferScanlines;
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void TIA::clearFrameBuffer()
+{
+  myFramebuffer.fill(0);
+  myFrontBuffer.fill(0);
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void TIA::update(uInt64 maxCycles)
 {
diff --git a/src/emucore/tia/TIA.hxx b/src/emucore/tia/TIA.hxx
index 0ff1afb67..a25a942d1 100644
--- a/src/emucore/tia/TIA.hxx
+++ b/src/emucore/tia/TIA.hxx
@@ -244,6 +244,8 @@ class TIA : public Device
     */
     uInt8* frameBuffer() { return myFramebuffer.data(); }
 
+    void clearFrameBuffer();
+
     /**
       Answers dimensional info about the framebuffer.
     */