diff --git a/Components/9918/9918.cpp b/Components/9918/9918.cpp
index b4815fd29..f39fd605b 100644
--- a/Components/9918/9918.cpp
+++ b/Components/9918/9918.cpp
@@ -647,8 +647,17 @@ void Base::draw_tms_text(int start, int end) {
 }
 
 void Base::draw_sms(int start, int end) {
-	if(!start && (row_ >= 16 || !master_system_.horizontal_scroll_lock)) {
-		pixel_target_ += master_system_.horizontal_scroll & 7;
+	// Shift the output window by the fine scroll amount, and fill in
+	// any border pixels that leaves on the left-hand side.
+	start -= master_system_.horizontal_scroll & 7;
+	end -= master_system_.horizontal_scroll & 7;
+	if(start < 0) {
+		while(start < end && start < 0) {
+			*pixel_target_ = master_system_.colour_ram[16 + background_colour_];
+			++pixel_target_;
+			++start;
+		}
+		if(start == end) return;
 	}
 
 	const int shift = start & 7;