diff --git a/src/mame/drivers/tumbleb.cpp b/src/mame/drivers/tumbleb.cpp
index c66dcf9aa1f..018fb21d3f3 100644
--- a/src/mame/drivers/tumbleb.cpp
+++ b/src/mame/drivers/tumbleb.cpp
@@ -2115,6 +2115,8 @@ MACHINE_RESET_MEMBER(tumbleb_state,tumbleb)
 	m_music_is_playing = 0;
 	m_tilebank = 0;
 	memset(m_control_0, 0, sizeof(m_control_0));
+	m_protbase = 0;
+	m_semicom_prot_offset = 0;
 }
 
 void tumbleb_state::tumblepb(machine_config &config)
diff --git a/src/mame/includes/mpu4.h b/src/mame/includes/mpu4.h
index b16980a73be..9efefa08ac0 100644
--- a/src/mame/includes/mpu4.h
+++ b/src/mame/includes/mpu4.h
@@ -132,6 +132,7 @@ public:
 		, m_mpu4leds(*this, "mpu4led%u", 0U)
 		, m_digits(*this, "digit%u", 0U)
 		, m_triacs(*this, "triac%u", 0U)
+		, m_current_chr_table(nullptr)
 	 { }
 
 	void init_m4default_alt();
diff --git a/src/mame/video/arcadia.cpp b/src/mame/video/arcadia.cpp
index 46bb94bd90e..cbfa442bc13 100644
--- a/src/mame/video/arcadia.cpp
+++ b/src/mame/video/arcadia.cpp
@@ -311,6 +311,7 @@ void arcadia_state::video_start()
 
 	m_line = 0;
 	std::fill(std::begin(m_reg.d.pal), std::end(m_reg.d.pal), 0);
+	m_shift = 0;
 }
 
 uint8_t arcadia_state::video_r(offs_t offset)
diff --git a/src/mame/video/vectrex.cpp b/src/mame/video/vectrex.cpp
index b9b3600f306..f0fa6031dbc 100644
--- a/src/mame/video/vectrex.cpp
+++ b/src/mame/video/vectrex.cpp
@@ -251,6 +251,7 @@ void vectrex_base_state::video_start()
 	m_ramp = 0;
 	std::fill(std::begin(m_analog), std::end(m_analog), 0);
 	m_point_index = 0;
+	m_lightpen_down = 0;
 }
 
 void vectrex_state::video_start()