diff --git a/src/mess/includes/pc.h b/src/mess/includes/pc.h
index cc7321f6f50..468f8721491 100644
--- a/src/mess/includes/pc.h
+++ b/src/mess/includes/pc.h
@@ -21,11 +21,12 @@ class pc_state : public driver_device
 public:
 	pc_state(const machine_config &mconfig, device_type type, const char *tag)
 		: driver_device(mconfig, type, tag),
+		m_maincpu(*this, "maincpu"),
 		m_dma8237(*this, "dma8237"),
 		m_pc_kbdc(*this, "pc_kbdc"),
 		m_speaker(*this, "speaker") { }
 
-	cpu_device *m_maincpu;
+	required_device<cpu_device> m_maincpu;
 	device_t *m_pic8259;
 	optional_device<am9517a_device> m_dma8237;
 	device_t *m_pit8253;
diff --git a/src/mess/machine/lynx.c b/src/mess/machine/lynx.c
index 8ba27be1940..75bae8b7a7b 100644
--- a/src/mess/machine/lynx.c
+++ b/src/mess/machine/lynx.c
@@ -804,7 +804,7 @@ static void lynx_blitter(running_machine &machine)
 		}
 	}
 
-	machine.scheduler().timer_set(machine.device<cpu_device>("maincpu")->cycles_to_attotime(state->m_blitter.memory_accesses), timer_expired_delegate(FUNC(lynx_state::lynx_blitter_timer),state));
+	machine.scheduler().timer_set(state->m_maincpu->cycles_to_attotime(state->m_blitter.memory_accesses), timer_expired_delegate(FUNC(lynx_state::lynx_blitter_timer),state));
 }
 
 
diff --git a/src/mess/machine/pc.c b/src/mess/machine/pc.c
index e8fef360d17..36c467272fd 100644
--- a/src/mess/machine/pc.c
+++ b/src/mess/machine/pc.c
@@ -1471,7 +1471,6 @@ MACHINE_START_MEMBER(pc_state,pc)
 {
 	m_pic8259 = machine().device("pic8259");
 	m_pit8253 = machine().device("pit8253");
-	m_maincpu = machine().device<cpu_device>("maincpu" );
 	m_maincpu->set_irq_acknowledge_callback(device_irq_acknowledge_delegate(FUNC(pc_state::pc_irq_callback),this));
 
 	pc_fdc_interface *fdc = machine().device<pc_fdc_interface>("fdc");
@@ -1505,7 +1504,6 @@ MACHINE_RESET_MEMBER(pc_state,pc)
 
 MACHINE_START_MEMBER(pc_state,mc1502)
 {
-	m_maincpu = machine().device<cpu_device>("maincpu" );
 	m_maincpu->set_irq_acknowledge_callback(device_irq_acknowledge_delegate(FUNC(pc_state::pc_irq_callback),this));
 
 	m_pic8259 = machine().device("pic8259");
@@ -1532,8 +1530,7 @@ MACHINE_START_MEMBER(pc_state,pcjr)
 {
 	pc_int_delay_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(pc_state::pcjr_delayed_pic8259_irq),this));
 	m_pcjr_watchdog = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(pc_state::pcjr_fdc_watchdog),this));
-	pcjr_keyb.keyb_signal_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(pc_state::pcjr_keyb_signal_callback),this));
-	m_maincpu = machine().device<cpu_device>("maincpu");
+	pcjr_keyb.keyb_signal_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(pc_state::pcjr_keyb_signal_callback),this));	
 	m_maincpu->set_irq_acknowledge_callback(device_irq_acknowledge_delegate(FUNC(pc_state::pc_irq_callback),this));
 
 	machine().device<upd765a_device>("upd765")->set_ready_line_connected(false);
diff --git a/src/mess/machine/pce.c b/src/mess/machine/pce.c
index e98bdaea90d..185242c95b2 100644
--- a/src/mess/machine/pce.c
+++ b/src/mess/machine/pce.c
@@ -1509,7 +1509,7 @@ static UINT8 pce_cd_get_cd_data_byte(running_machine &machine)
 		if ( pce_cd.scsi_IO )
 		{
 			pce_cd.scsi_ACK = 1;
-			machine.scheduler().timer_set(machine.device<cpu_device>("maincpu")->cycles_to_attotime(15), timer_expired_delegate(FUNC(pce_state::pce_cd_clear_ack),state));
+			machine.scheduler().timer_set(state->m_maincpu->cycles_to_attotime(15), timer_expired_delegate(FUNC(pce_state::pce_cd_clear_ack),state));
 		}
 	}
 	return data;
diff --git a/src/mess/video/fmtowns.c b/src/mess/video/fmtowns.c
index de9796d9e8a..4fdcbd6e1af 100644
--- a/src/mess/video/fmtowns.c
+++ b/src/mess/video/fmtowns.c
@@ -894,7 +894,7 @@ static void draw_sprites(running_machine &machine, const rectangle* rect)
 		state->m_video.towns_sprite_page = 0;
 
 	state->m_video.towns_sprite_flag = 1;  // we are now drawing
-	state->m_video.sprite_timer->adjust(machine.device<cpu_device>("maincpu")->cycles_to_attotime(128 * (1025-sprite_limit)));
+	state->m_video.sprite_timer->adjust(state->m_maincpu->cycles_to_attotime(128 * (1025-sprite_limit)));
 }
 
 static void towns_crtc_draw_scan_layer_hicolour(running_machine &machine, bitmap_rgb32 &bitmap,const rectangle* rect,int layer,int line,int scanline)