diff --git a/tools.py b/tools.py
index ec117bb9723fe9ffefe8ba8e6b4bc7dd0e4da1e8..9562d2a045bfa47a825ebe4631c26255ed45a6a8 100644
--- a/tools.py
+++ b/tools.py
@@ -787,7 +787,7 @@ def _laser_switch(boolean):
     """
     Switch on (True) or off (False) the repumping laser.
     """
-    stm.set_650()
+    self.stm.set_650()
 
 
 def _contrast_and_noise():