diff --git a/src/mame/sigma/sigmab31.cpp b/src/mame/sigma/sigmab31.cpp
index 142bb6ce78858..41bc5dc7031d1 100644
--- a/src/mame/sigma/sigmab31.cpp
+++ b/src/mame/sigma/sigmab31.cpp
@@ -106,7 +106,9 @@ class sigmab31_state : public driver_device
 public:
 	sigmab31_state(const machine_config &mconfig, device_type type, const char *tag) :
 		driver_device(mconfig, type, tag),
-		m_maincpu(*this, "maincpu")
+		m_maincpu(*this, "maincpu"),
+		m_audiocpu(*this, "audiocpu")
+
 	{ }
 
 	void sigmab31(machine_config &config);
@@ -116,18 +118,31 @@ class sigmab31_state : public driver_device
 	virtual void machine_reset() override ATTR_COLD;
 
 private:
-	void prg_map(address_map &map) ATTR_COLD;
+	void main_map(address_map &map) ATTR_COLD;
+	void sound_map (address_map &map) ATTR_COLD;
 
 	required_device<cpu_device>     m_maincpu;
+	required_device<cpu_device>     m_audiocpu;
+
 };
 
 
-void sigmab31_state::prg_map(address_map &map)
+void sigmab31_state::main_map(address_map &map)
 {
 	map(0x6000, 0xf6ff).rom();
 	map(0xf800, 0xffff).rom();
 }
 
+void sigmab31_state::sound_map (address_map &map)
+{
+	map(0x0000, 0x1fff).ram();
+//	map(0x6020, 0x6027).rw(m_6840ptm_2, FUNC(ptm6840_device::read), FUNC(ptm6840_device::write));
+//	map(0x6030, 0x6030).w(FUNC(sigmab31_state::audiocpu_irq_ack_w));
+//	map(0x6050, 0x6050).r("soundlatch", FUNC(generic_latch_8_device::read));
+	map(0x6060, 0x6061).rw("ymsnd", FUNC(ym3812_device::read), FUNC(ym3812_device::write));
+	map(0x8000, 0xffff).rom().region("audiocpu", 0);
+}
+
 
 static INPUT_PORTS_START( cptlucky )
 	PORT_START("IN0")
@@ -173,7 +188,10 @@ void sigmab31_state::machine_reset()
 void sigmab31_state::sigmab31(machine_config &config)
 {
 	MC6809(config, m_maincpu, 8_MHz_XTAL);
-	m_maincpu->set_addrmap(AS_PROGRAM, &sigmab31_state::prg_map);
+	m_maincpu->set_addrmap(AS_PROGRAM, &sigmab31_state::main_map);
+	
+	MC6809(config, m_audiocpu, XTAL(8'000'000));
+	m_audiocpu->set_addrmap(AS_PROGRAM, &sigmab31_state::sound_map );
 
 	PTM6840(config, "6840ptm_1", 8_MHz_XTAL / 8);
 
@@ -193,7 +211,7 @@ ROM_START( cptlucky )
 	ROM_REGION( 0x10000, "maincpu", 0 )
 	ROM_LOAD( "b325107-084_captain_lucky_l93-0091.70", 0x00000, 0x10000, CRC(84c2ab4e) SHA1(3d388ba1c8e4718ca95df45f59d0315887385a27) )
 
-	ROM_REGION( 0x8000, "opl", 0 )
+	ROM_REGION( 0x8000, "audiocpu", 0 )
 	ROM_LOAD( "m-slot_03-00_l89-1625.57", 0x00000, 0x8000, CRC(268c8a7c) SHA1(90903428d6c0af3ebdcb462e80a7c28dc4ee7af2) )
 ROM_END