diff --git a/src/emu/machine/am9517a.c b/src/emu/machine/am9517a.c
index 0f4108b968f..a2cde90c11d 100644
--- a/src/emu/machine/am9517a.c
+++ b/src/emu/machine/am9517a.c
@@ -433,6 +433,11 @@ void am9517a_device::device_start()
 		m_channel[i].m_in_ior_func.resolve(m_in_ior_cb[i], *this);
 		m_channel[i].m_out_iow_func.resolve(m_out_iow_cb[i], *this);
 		m_channel[i].m_out_dack_func.resolve(m_out_dack_cb[i], *this);
+		m_channel[i].m_address = 0;
+		m_channel[i].m_count = 0;
+		m_channel[i].m_base_address = 0;
+		m_channel[i].m_base_count = 0;
+		m_channel[i].m_mode = 0;
 	}
 
 	// state saving