diff --git a/src/video/vid_ega_render.c b/src/video/vid_ega_render.c
index 5e6337a48..0ab9b5b3f 100644
--- a/src/video/vid_ega_render.c
+++ b/src/video/vid_ega_render.c
@@ -76,6 +76,9 @@ ega_render_overscan_left(ega_t *ega)
 {
     int i;
 
+    if ((ega->displine + ega->y_add) < 0)
+	return;
+
     if (ega->scrblank || (ega->hdisp == 0))
 	return;
 
@@ -89,6 +92,9 @@ ega_render_overscan_right(ega_t *ega)
 {
     int i, right;
 
+    if ((ega->displine + ega->y_add) < 0)
+	return;
+
     if (ega->scrblank || (ega->hdisp == 0))
 	return;
 
diff --git a/src/video/vid_svga_render.c b/src/video/vid_svga_render.c
index 30b274067..c76bf2d72 100644
--- a/src/video/vid_svga_render.c
+++ b/src/video/vid_svga_render.c
@@ -69,6 +69,9 @@ svga_render_overscan_left(svga_t *svga)
 {
     int i;
 
+    if ((svga->displine + svga->y_add) < 0)
+	return;
+
     if (svga->scrblank || (svga->hdisp == 0))
 	return;
 
@@ -82,6 +85,9 @@ svga_render_overscan_right(svga_t *svga)
 {
     int i, right;
 
+    if ((svga->displine + svga->y_add) < 0)
+	return;
+
     if (svga->scrblank || (svga->hdisp == 0))
 	return;