diff --git a/src/mame/drivers/m92.cpp b/src/mame/drivers/m92.cpp
index be44923f8d1..ad1239ca675 100644
--- a/src/mame/drivers/m92.cpp
+++ b/src/mame/drivers/m92.cpp
@@ -613,6 +613,17 @@ static INPUT_PORTS_START( lethalth )
 INPUT_PORTS_END
 
 
+static INPUT_PORTS_START( thndblst )
+	PORT_INCLUDE(lethalth)
+
+	PORT_MODIFY("DSW")
+	/* Dip switch bank 1 */
+	PORT_DIPNAME( 0x0010, 0x0000, "Continuous Play" ) PORT_DIPLOCATION("SW1:5") /* manual says Unused */
+	PORT_DIPSETTING(      0x0000, DEF_STR( On ) )
+	PORT_DIPSETTING(      0x0010, DEF_STR( Off ) )
+INPUT_PORTS_END
+
+
 static INPUT_PORTS_START( hook )
 	PORT_INCLUDE(m92_4player)
 
@@ -2207,7 +2218,7 @@ GAME( 1991, bmaster,  0,        bmaster,       bmaster, m92_state,  m92,      RO
 GAME( 1991, crossbld, bmaster,  bmaster,       bmaster, m92_state,  m92,      ROT0,   "Irem",         "Cross Blades! (Japan)", MACHINE_SUPPORTS_SAVE | MACHINE_NO_COCKTAIL)
 
 GAME( 1991, lethalth, 0,        lethalth,      lethalth, m92_state, lethalth, ROT270, "Irem",         "Lethal Thunder (World)", MACHINE_SUPPORTS_SAVE | MACHINE_NO_COCKTAIL )
-GAME( 1991, thndblst, lethalth, lethalth,      lethalth, m92_state, lethalth, ROT270, "Irem",         "Thunder Blaster (Japan)", MACHINE_SUPPORTS_SAVE | MACHINE_NO_COCKTAIL )
+GAME( 1991, thndblst, lethalth, lethalth,      thndblst, m92_state, lethalth, ROT270, "Irem",         "Thunder Blaster (Japan)", MACHINE_SUPPORTS_SAVE | MACHINE_NO_COCKTAIL )
 
 GAME( 1992, uccops,   0,        uccops,        uccops, m92_state,   m92,      ROT0,   "Irem",         "Undercover Cops (World)", MACHINE_SUPPORTS_SAVE | MACHINE_NO_COCKTAIL )
 GAME( 1992, uccopsu,  uccops,   uccops,        uccops, m92_state,   m92,      ROT0,   "Irem",         "Undercover Cops (US)", MACHINE_SUPPORTS_SAVE | MACHINE_NO_COCKTAIL )