diff --git a/src/mame/drivers/1943.c b/src/mame/drivers/1943.c
index f5f068e3584..79c7139686b 100644
--- a/src/mame/drivers/1943.c
+++ b/src/mame/drivers/1943.c
@@ -14,6 +14,13 @@
 
 /*
 
+    SERVICE TEST INFORMATION:
+
+    - To access the unreachable tests (#4-7) in the Service Test, when starting
+    up the machine after it has been set into Test Mode, hold down the left
+    coin switch.
+
+
     TODO:
 
     - use priority PROM for drawing sprites