diff --git a/src/mess/drivers/compis.c b/src/mess/drivers/compis.c
index 009233a41e8..52231c7218a 100644
--- a/src/mess/drivers/compis.c
+++ b/src/mess/drivers/compis.c
@@ -168,6 +168,7 @@ static ADDRESS_MAP_START( compis_io, AS_IO, 16, compis_state )
 	AM_RANGE( 0x0330, 0x0333) AM_DEVREADWRITE8("upd7220", upd7220_device, read, write, 0x00ff) /* GDC 82720 PCS6:6     */
 	AM_RANGE( 0x0340, 0x0343) AM_DEVICE8("i8272a", i8272a_device, map, 0x00ff)  /* iSBX0 (J8) FDC 8272      */
 	AM_RANGE( 0x0350, 0x0351) AM_DEVREADWRITE8("i8272a", i8272a_device, mdma_r, mdma_w, 0x00ff) /* iSBX0 (J8) DMA ACK       */
+	AM_RANGE( 0x034e, 0x034f) AM_READWRITE8(fdc_mon_r, fdc_mon_w, 0x00ff)
 //{ 0x0100, 0x017e, compis_null_r },    /* RTC              */
 //{ 0x0180, 0x01ff, compis_null_r },    /* PCS3?            */
 //{ 0x0200, 0x027f, compis_null_r },    /* Reserved         */
@@ -349,7 +350,7 @@ static MACHINE_CONFIG_START( compis, compis_state )
 	MCFG_CPU_PROGRAM_MAP(compis_mem)
 	MCFG_CPU_IO_MAP(compis_io)
 	MCFG_CPU_VBLANK_INT_DRIVER("screen", compis_state,  compis_vblank_int)
-	MCFG_80186_IRQ_SLAVE_ACK(DEVREAD8(DEVICE_SELF_OWNER, compis_state, compis_irq_callback))
+	MCFG_80186_IRQ_SLAVE_ACK(DEVREAD8(DEVICE_SELF, compis_state, compis_irq_callback))
 	//MCFG_CPU_CONFIG(i86_address_mask)
 
 	//MCFG_QUANTUM_TIME(attotime::from_hz(60))
@@ -394,7 +395,7 @@ static MACHINE_CONFIG_START( compis2, compis_state )
 	MCFG_CPU_PROGRAM_MAP(compis_mem)
 	MCFG_CPU_IO_MAP(compis_io)
 	MCFG_CPU_VBLANK_INT_DRIVER("screen", compis_state,  compis_vblank_int)
-	MCFG_80186_IRQ_SLAVE_ACK(DEVREAD8(DEVICE_SELF_OWNER, compis_state, compis_irq_callback))
+	MCFG_80186_IRQ_SLAVE_ACK(DEVREAD8(DEVICE_SELF, compis_state, compis_irq_callback))
 	//MCFG_CPU_CONFIG(i86_address_mask)
 
 	//MCFG_QUANTUM_TIME(attotime::from_hz(60))
diff --git a/src/mess/drivers/rmnimbus.c b/src/mess/drivers/rmnimbus.c
index b33834b3a9d..c9baf805f2f 100644
--- a/src/mess/drivers/rmnimbus.c
+++ b/src/mess/drivers/rmnimbus.c
@@ -286,7 +286,7 @@ static MACHINE_CONFIG_START( nimbus, rmnimbus_state )
 	MCFG_CPU_ADD(MAINCPU_TAG, I80186, 10000000)
 	MCFG_CPU_PROGRAM_MAP(nimbus_mem)
 	MCFG_CPU_IO_MAP(nimbus_io)
-	MCFG_80186_IRQ_SLAVE_ACK(DEVREAD8(DEVICE_SELF_OWNER, rmnimbus_state, cascade_callback))
+	MCFG_80186_IRQ_SLAVE_ACK(DEVREAD8(DEVICE_SELF, rmnimbus_state, cascade_callback))
 
 	MCFG_CPU_ADD(IOCPU_TAG, I8031, 11059200)
 	MCFG_CPU_PROGRAM_MAP(nimbus_iocpu_mem)
diff --git a/src/mess/includes/compis.h b/src/mess/includes/compis.h
index ffaed5d4557..78a6ee1eff3 100644
--- a/src/mess/includes/compis.h
+++ b/src/mess/includes/compis.h
@@ -174,6 +174,9 @@ public:
 //	void internal_timer_sync(int which);
 //	void handle_eoi(int data);
 	void compis_fdc_tc(int state);
+	DECLARE_READ8_MEMBER(fdc_mon_r);
+	DECLARE_WRITE8_MEMBER(fdc_mon_w);
+	bool m_mon;
 
 	void fdc_irq(bool state);
 	void fdc_drq(bool state);
diff --git a/src/mess/machine/compis.c b/src/mess/machine/compis.c
index 583081394f2..8b6949ba956 100644
--- a/src/mess/machine/compis.c
+++ b/src/mess/machine/compis.c
@@ -192,7 +192,18 @@ void compis_state::fdc_drq(bool state)
 	}
 }
 
+WRITE8_MEMBER(compis_state::fdc_mon_w)
+{
+	m_mon = data & 1;
 
+	m_fdc->subdevice<floppy_connector>("0")->get_device()->mon_w(m_mon);
+	m_fdc->subdevice<floppy_connector>("1")->get_device()->mon_w(m_mon);
+}
+
+READ8_MEMBER(compis_state::fdc_mon_r)
+{
+	return m_mon;
+}
 /*-------------------------------------------------------------------------*/
 /* Bit 0: J5-4                                                             */
 /* Bit 1: J5-5                                                     */
@@ -1293,6 +1304,7 @@ void compis_state::machine_start()
 	/* CPU */
 	compis_cpu_init();
 	m_fdc->setup_intrq_cb(i8272a_device::line_cb(FUNC(compis_state::fdc_irq), this));
+	m_mon = false;
 }
 /*-------------------------------------------------------------------------*/
 /* Name: compis                                                            */