diff --git a/src/emu/machine/mos6551.c b/src/emu/machine/mos6551.c
index 4aae612659e..2871756eee3 100644
--- a/src/emu/machine/mos6551.c
+++ b/src/emu/machine/mos6551.c
@@ -34,7 +34,9 @@ mos6551_device::mos6551_device(const machine_config &mconfig, const char *tag, d
 	m_dsr(1),
 	m_dcd(1),
 	m_rxd(1),
-	m_tx_output(OUTPUT_MARK)
+	m_tx_state(STATE_START),
+	m_tx_output(OUTPUT_MARK),
+	m_tx_counter(0)
 {
 }