diff --git a/src/mame/machine/apple3.cpp b/src/mame/machine/apple3.cpp
index c1cb5e0aa27..695e5f1ccfe 100644
--- a/src/mame/machine/apple3.cpp
+++ b/src/mame/machine/apple3.cpp
@@ -814,7 +814,7 @@ uint8_t apple3_state::apple3_memory_r(offs_t offset)
 		{
 			rv = m_bank9[offset - 0xc100];
 		}
-		else
+		else if (!machine().side_effects_disabled())
 		{
 			/* now identify the device */
 			device_a2bus_card_interface *slotdevice = m_a2bus->get_a2bus_card((offset>>8) & 0x7);