diff --git a/src/mame/video/bionicc.c b/src/mame/video/bionicc.c
index fc759b953ef..6833fbf3949 100644
--- a/src/mame/video/bionicc.c
+++ b/src/mame/video/bionicc.c
@@ -131,8 +131,11 @@ WRITE16_HANDLER( bionicc_txvideoram_w )
 
 WRITE16_HANDLER( bionicc_paletteram_w )
 {
+	/* The bottom bits are 'intensity' here, but level 2 of Top Secret shows that even
+	when intensity is zero the colour is not reduced to pure black, (the sky should stay
+	at dark blue rather than absolute black) */
 	data = COMBINE_DATA(&paletteram16[offset]);
-	paletteram16_RRRRGGGGBBBBIIII_word_w(offset,(data & 0xfff0) | ((data & 0x0007) << 1),0);
+	paletteram16_RRRRGGGGBBBBIIII_word_w(offset,(data & 0xfff0) | ((data & 0x0007) << 1) | 1, 0);
 }
 
 WRITE16_HANDLER( bionicc_scroll_w )