diff --git a/src/emu/machine/rp5c01.c b/src/emu/machine/rp5c01.c
index 65e1a809fe0..7c528feb3a5 100644
--- a/src/emu/machine/rp5c01.c
+++ b/src/emu/machine/rp5c01.c
@@ -242,6 +242,7 @@ void rp5c01_device::device_start()
 void rp5c01_device::device_reset()
 {
 	memset(m_reg, 0, sizeof(m_reg));
+	memset(m_ram, 0, sizeof(m_ram));
 	set_current_time(machine());
 }