diff --git a/Mac/Lib/test/AEservertest.py b/Mac/Lib/test/AEservertest.py
index 75137380bf3..1e3e508a4fb 100644
--- a/Mac/Lib/test/AEservertest.py
+++ b/Mac/Lib/test/AEservertest.py
@@ -42,14 +42,14 @@ def myaskstring(str, default=''):
 
 def main():
 	echo = EchoServer()
-	yield = MacOS.EnableAppswitch(-1)		# Disable Python's own "event handling"
+	savepars = MacOS.SchedParams(0, 0)		# Disable Python's own "event handling"
 	try:
 		try:
 			echo.mainloop(everyEvent, 0)
 		except Quit:
 			pass
 	finally:
-		MacOS.EnableAppswitch(yield)	# Let Python have a go at events
+		apply(MacOS.SchedParams, savepars)	# Let Python have a go at events
 		echo.close()
 
 
diff --git a/Mac/Lib/test/ctbtest.py b/Mac/Lib/test/ctbtest.py
index 0f3cd90fc2b..cb1b5068e08 100644
--- a/Mac/Lib/test/ctbtest.py
+++ b/Mac/Lib/test/ctbtest.py
@@ -16,7 +16,7 @@ def main():
 		print 'Communications Toolbox not available'
 		sys.exit(1)
 	# Disable Python's event processing (we do that)
-	MacOS.EnableAppswitch(0)
+	MacOS.SchedParams(1, 0)
 	print 'Minimal terminal emulator V1.0'
 	print '(type command-Q to exit)'
 	print
diff --git a/Mac/Lib/test/echo.py b/Mac/Lib/test/echo.py
index 7376238b3eb..1bad3e137d4 100644
--- a/Mac/Lib/test/echo.py
+++ b/Mac/Lib/test/echo.py
@@ -33,11 +33,11 @@ def mymessage(str):
 
 def main():
 	echo = EchoServer()
-	yield = MacOS.EnableAppswitch(-1)		# Disable Python's own "event handling"
+	saveparams = MacOS.SchedParams(0, 0)	# Disable Python's own "event handling"
 	try:
 		echo.mainloop(everyEvent, 0)
 	finally:
-		MacOS.EnableAppswitch(yield)	# Let Python have a go at events
+		apply(MacOS.SchedParams, saveparams)	# Let Python have a go at events
 		echo.close()
 
 
diff --git a/Mac/Lib/test/tae.py b/Mac/Lib/test/tae.py
index 73c36b92418..4789672494f 100644
--- a/Mac/Lib/test/tae.py
+++ b/Mac/Lib/test/tae.py
@@ -11,7 +11,7 @@ import macfs
 import sys
 import MacOS
 
-MacOS.EnableAppswitch(0)
+MacOS.SchedParams(1, 0)
 
 def aehandler(request, reply):
 	tosend = []