diff --git a/src/devices/bus/hp_hil/hlemouse.cpp b/src/devices/bus/hp_hil/hlemouse.cpp
index 2303f011272..a54ef33a0e7 100644
--- a/src/devices/bus/hp_hil/hlemouse.cpp
+++ b/src/devices/bus/hp_hil/hlemouse.cpp
@@ -41,6 +41,8 @@ hle_hp_46060b_device::hle_hp_46060b_device(machine_config const &mconfig, char c
 void hle_hp_46060b_device::device_reset()
 {
 	m_fifo.clear();
+
+	mouse_x_delta = mouse_y_delta = 0;
 }
 
 int hle_hp_46060b_device::hil_poll()
diff --git a/src/devices/machine/arm_iomd.cpp b/src/devices/machine/arm_iomd.cpp
index e33863976ba..d6ce9557716 100644
--- a/src/devices/machine/arm_iomd.cpp
+++ b/src/devices/machine/arm_iomd.cpp
@@ -308,7 +308,10 @@ void arm_iomd_device::device_reset()
 
 	m_sound_dma_on = false;
 	for (i=0; i<sounddma_ch_size; i++)
+	{
 		m_sndbuffer_ok[i] = false;
+		m_sndcur_reg[i] = 0;
+	}
 
 	// ...
 }
diff --git a/src/mame/machine/mct_adr.cpp b/src/mame/machine/mct_adr.cpp
index fba6bd02af8..9de43725ea9 100644
--- a/src/mame/machine/mct_adr.cpp
+++ b/src/mame/machine/mct_adr.cpp
@@ -177,6 +177,9 @@ void mct_adr_device::device_reset()
 	m_memory_refresh_rate = 0x18186;
 	m_nvram_protect = 0x7;
 
+	m_dma_invalid_address = 0;
+	m_dma_memory_failed_address = 0;
+
 	m_isr = 0;
 	m_imr = 0x10; // firmware diagnostic expects network interrupts to be unmasked at boot