diff --git a/src/mess/machine/kb_keytro.c b/src/mess/machine/kb_keytro.c
index 89e0edaff19..70c65dc4fe1 100644
--- a/src/mess/machine/kb_keytro.c
+++ b/src/mess/machine/kb_keytro.c
@@ -429,6 +429,7 @@ void pc_kbd_keytronic_pc3270_device::device_reset()
 {
 	/* set default values */
 	m_p3 = 0xff;
+	m_last_write_addr = 0;
 }