diff --git a/src/emu/video/mc6847.c b/src/emu/video/mc6847.c
index 730499cf0e8..8bf4a5e3c44 100644
--- a/src/emu/video/mc6847.c
+++ b/src/emu/video/mc6847.c
@@ -638,6 +638,7 @@ void mc6847_base_device::device_start()
 	setup_fixed_mode(config->m_in_css_func,     MODE_CSS);
 
 	m_dirty = false;
+	m_mode = 0;
 
 	/* state save */
 	save_item(NAME(m_dirty));