diff --git a/src/mame/drivers/missb2.cpp b/src/mame/drivers/missb2.cpp
index a7848e92fe4..5b9480a7c7a 100644
--- a/src/mame/drivers/missb2.cpp
+++ b/src/mame/drivers/missb2.cpp
@@ -492,6 +492,9 @@ static MACHINE_CONFIG_START( missb2 )
 	/* sound hardware */
 	MCFG_SPEAKER_STANDARD_MONO("mono")
 
+	MCFG_INPUT_MERGER_ALL_HIGH("soundnmi")
+	MCFG_INPUT_MERGER_OUTPUT_HANDLER(INPUTLINE("audiocpu", INPUT_LINE_NMI))
+
 	MCFG_GENERIC_LATCH_8_ADD("main_to_sound")
 	MCFG_GENERIC_LATCH_DATA_PENDING_CB(DEVWRITELINE("soundnmi", input_merger_device, in_w<0>))