diff --git a/src/burn/drv/pre90s/d_armedf.cpp b/src/burn/drv/pre90s/d_armedf.cpp
index 96cc071a5..7144e1381 100644
--- a/src/burn/drv/pre90s/d_armedf.cpp
+++ b/src/burn/drv/pre90s/d_armedf.cpp
@@ -559,11 +559,11 @@ void __fastcall armedf_write_port(UINT16 port, UINT8 data)
 		return;
 
 		case 0x02:
-			DACSignedWrite(0, data);
+			if (data!=0x7f && data!=0x77) DACSignedWrite(0, data);
 		return;
 
 		case 0x03:
-			DACSignedWrite(1, data);
+			if (data!=0x7f && data!=0x77) DACSignedWrite(1, data);
 		return;
 	}
 }