diff --git a/src/mame/drivers/overdriv.c b/src/mame/drivers/overdriv.c
index 935a8085f05..12c41e26f43 100644
--- a/src/mame/drivers/overdriv.c
+++ b/src/mame/drivers/overdriv.c
@@ -5,6 +5,7 @@
     driver by Nicola Salmoria
 
     Notes:
+    - irq source for main CPU aren't understood, needs HW tests.
     - Missing road (two unemulated K053250)
     - Visible area and relative placement of sprites and tiles is most likely wrong.
     - Test mode doesn't work well with 3 IRQ5 per frame, the ROM check doesn't work
@@ -20,7 +21,6 @@
 
 #include "emu.h"
 #include "cpu/m68000/m68000.h"
-#include "deprecat.h"
 #include "video/konicdev.h"
 #include "machine/eeprom.h"
 #include "cpu/m6809/m6809.h"
@@ -72,13 +72,16 @@ static WRITE16_HANDLER( eeprom_w )
 	}
 }
 
-
-static INTERRUPT_GEN( cpuA_interrupt )
+static TIMER_DEVICE_CALLBACK( overdriv_cpuA_scanline )
 {
-	if (cpu_getiloops(device))
-		device_set_input_line(device, 5, HOLD_LINE);
-	else
-		device_set_input_line(device, 4, HOLD_LINE);
+	int scanline = param;
+
+	/* TODO: irqs routines are TOO slow right now, it ends up firing spurious irqs for whatever reason (shared ram fighting?) */
+	/*       this is a temporary solution to get rid of deprecat.h and the crashes, but also makes the game timer to be too slow */
+	if(scanline == 256 && timer.machine().primary_screen->frame_number() & 1) // vblank-out irq
+		cputag_set_input_line(timer.machine(), "maincpu", 4, HOLD_LINE);
+	else if((scanline % 128) == 0) // timer irq
+		cputag_set_input_line(timer.machine(), "maincpu", 5, HOLD_LINE);
 }
 
 static INTERRUPT_GEN( cpuB_interrupt )
@@ -155,7 +158,6 @@ static WRITE16_HANDLER( overdriv_cpuB_irq6_w )
 	device_set_input_line(state->m_subcpu, 6, HOLD_LINE);
 }
 
-
 static ADDRESS_MAP_START( overdriv_master_map, AS_PROGRAM, 16 )
 	AM_RANGE(0x000000, 0x03ffff) AM_ROM
 	AM_RANGE(0x040000, 0x043fff) AM_RAM					/* work RAM */
@@ -164,7 +166,7 @@ static ADDRESS_MAP_START( overdriv_master_map, AS_PROGRAM, 16 )
 	AM_RANGE(0x0c0002, 0x0c0003) AM_READ_PORT("SYSTEM")
 	AM_RANGE(0x0e0000, 0x0e0001) AM_WRITENOP			/* unknown (always 0x30) */
 	AM_RANGE(0x100000, 0x10001f) AM_WRITENOP			/* 053252? (LSB) */
-	AM_RANGE(0x140000, 0x140001) AM_WRITE(watchdog_reset16_w)
+	AM_RANGE(0x140000, 0x140001) AM_WRITENOP //watchdog reset?
 	AM_RANGE(0x180000, 0x180001) AM_READ_PORT("PADDLE")
 	AM_RANGE(0x1c0000, 0x1c001f) AM_DEVWRITE8("k051316_1", k051316_ctrl_w, 0xff00)
 	AM_RANGE(0x1c8000, 0x1c801f) AM_DEVWRITE8("k051316_2", k051316_ctrl_w, 0xff00)
@@ -329,22 +331,24 @@ static MACHINE_RESET( overdriv )
 	cputag_set_input_line(machine, "sub", INPUT_LINE_RESET, ASSERT_LINE);
 }
 
+
+
 static MACHINE_CONFIG_START( overdriv, overdriv_state )
 
 	/* basic machine hardware */
 	MCFG_CPU_ADD("maincpu", M68000,24000000/2)	/* 12 MHz */
 	MCFG_CPU_PROGRAM_MAP(overdriv_master_map)
-	MCFG_CPU_VBLANK_INT_HACK(cpuA_interrupt,4)	/* ??? IRQ 4 is vblank, IRQ 5 of unknown origin */
+	MCFG_TIMER_ADD_SCANLINE("scantimer", overdriv_cpuA_scanline, "screen", 0, 1)
 
 	MCFG_CPU_ADD("sub", M68000,24000000/2)	/* 12 MHz */
 	MCFG_CPU_PROGRAM_MAP(overdriv_slave_map)
 	MCFG_CPU_VBLANK_INT("screen", cpuB_interrupt)	/* IRQ 5 and 6 are generated by the main CPU. */
-								/* IRQ 5 is used only in test mode, to request the checksums of the gfx ROMs. */
-	MCFG_CPU_ADD("audiocpu", M6809,3579545/2)	/* 1.789 MHz?? This might be the right speed, but ROM testing */
-						/* takes a little too much (the counter wraps from 0000 to 9999). */
-						/* This might just mean that the video refresh rate is less than */
-						/* 60 fps, that's how I fixed it for now. */
-	MCFG_CPU_PROGRAM_MAP(overdriv_sound_map)
+													/* IRQ 5 is used only in test mode, to request the checksums of the gfx ROMs. */
+
+	MCFG_CPU_ADD("audiocpu", M6809,3579545)		/* 1.789 MHz?? This might be the right speed, but ROM testing */
+	MCFG_CPU_PROGRAM_MAP(overdriv_sound_map) 	/* takes a little too much (the counter wraps from 0000 to 9999). */
+												/* This might just mean that the video refresh rate is less than */
+												/* 60 fps, that's how I fixed it for now. */
 
 	MCFG_QUANTUM_TIME(attotime::from_hz(12000))
 
@@ -359,9 +363,9 @@ static MACHINE_CONFIG_START( overdriv, overdriv_state )
 
 	MCFG_SCREEN_ADD("screen", RASTER)
 	MCFG_SCREEN_REFRESH_RATE(59)
-	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(0))
+	MCFG_SCREEN_VBLANK_TIME(ATTOSECONDS_IN_USEC(2500))
 	MCFG_SCREEN_FORMAT(BITMAP_FORMAT_INDEXED16)
-	MCFG_SCREEN_SIZE(64*8, 32*8)
+	MCFG_SCREEN_SIZE(64*8, 40*8)
 	MCFG_SCREEN_VISIBLE_AREA(13*8, (64-13)*8-1, 0*8, 32*8-1 )
 	MCFG_SCREEN_UPDATE(overdriv)