diff --git a/src/mame/drivers/wardner.cpp b/src/mame/drivers/wardner.cpp
index 7319a0610e4..c565901ed69 100644
--- a/src/mame/drivers/wardner.cpp
+++ b/src/mame/drivers/wardner.cpp
@@ -162,6 +162,9 @@ private:
 
 	void wardner_bank_w(uint8_t data);
 
+	DECLARE_WRITE_LINE_MEMBER(wardner_vblank_irq);
+	DECLARE_WRITE_LINE_MEMBER(int_enable_w);
+
 	void dsp_io_map(address_map &map);
 	void dsp_program_map(address_map &map);
 	void main_bank_map(address_map &map);
@@ -172,6 +175,20 @@ private:
 };
 
 
+WRITE_LINE_MEMBER(wardner_state::wardner_vblank_irq)
+{
+	if (state && m_intenable)
+		m_maincpu->set_input_line(0, ASSERT_LINE);
+}
+
+WRITE_LINE_MEMBER(wardner_state::int_enable_w)
+{
+	m_intenable = state;
+	if (!state)
+		m_maincpu->set_input_line(0, CLEAR_LINE);
+}
+
+
 /***************************** Z80 Main Memory Map **************************/
 
 void wardner_state::wardner_bank_w(uint8_t data)
diff --git a/src/mame/includes/twincobr.h b/src/mame/includes/twincobr.h
index 208281b9408..8ec4e59bd28 100644
--- a/src/mame/includes/twincobr.h
+++ b/src/mame/includes/twincobr.h
@@ -127,7 +127,6 @@ protected:
 	TILE_GET_INFO_MEMBER(get_tx_tile_info);
 	u32 screen_update(screen_device &screen, bitmap_rgb32 &bitmap, const rectangle &cliprect);
 	DECLARE_WRITE_LINE_MEMBER(twincobr_vblank_irq);
-	DECLARE_WRITE_LINE_MEMBER(wardner_vblank_irq);
 	void twincobr_create_tilemaps();
 	DECLARE_WRITE_LINE_MEMBER(display_on_w);
 	DECLARE_WRITE_LINE_MEMBER(flipscreen_w);
diff --git a/src/mame/machine/twincobr.cpp b/src/mame/machine/twincobr.cpp
index 3cf7e369451..9fc69b343d8 100644
--- a/src/mame/machine/twincobr.cpp
+++ b/src/mame/machine/twincobr.cpp
@@ -18,19 +18,7 @@
 WRITE_LINE_MEMBER(twincobr_state::twincobr_vblank_irq)
 {
 	if (state && m_intenable)
-	{
-		m_intenable = 0;
-		m_maincpu->set_input_line(M68K_IRQ_4, HOLD_LINE);
-	}
-}
-
-WRITE_LINE_MEMBER(twincobr_state::wardner_vblank_irq)
-{
-	if (state && m_intenable)
-	{
-		m_intenable = 0;
-		m_maincpu->set_input_line(0, HOLD_LINE);
-	}
+		m_maincpu->set_input_line(M68K_IRQ_4, ASSERT_LINE);
 }
 
 
@@ -189,6 +177,8 @@ READ_LINE_MEMBER(twincobr_state::twincobr_bio_r)
 WRITE_LINE_MEMBER(twincobr_state::int_enable_w)
 {
 	m_intenable = state;
+	if (!state)
+		m_maincpu->set_input_line(M68K_IRQ_4, CLEAR_LINE);
 }
 
 WRITE_LINE_MEMBER(twincobr_state::dsp_int_w)