diff --git a/py65/devices/mpu6502.py b/py65/devices/mpu6502.py
index b7954e59..d10c4e4e 100644
--- a/py65/devices/mpu6502.py
+++ b/py65/devices/mpu6502.py
@@ -1,6 +1,6 @@
 from py65.utils.conversions import itoa
 from py65.utils.devices import make_instruction_decorator
-from py65 import disassembler
+
 
 class MPU:
     # vectors
@@ -41,8 +41,6 @@ def __init__(self, memory=None, pc=0x0000):
         self.memory = memory
         self.start_pc = pc
 
-        self.disassembler = disassembler.Disassembler(self)
-
         # init
         self.reset()
 
@@ -57,11 +55,8 @@ def __repr__(self):
         return self.reprformat() % (indent, self.name, self.pc, self.a,
                                     self.x, self.y, self.sp, flags)
 
-    def step(self, trace=False):
+    def step(self):
         instructCode = self.memory[self.pc]
-        if trace:
-            print self, "$%04X: %s" % (
-                self.pc, self.disassembler.instruction_at(self.pc)[1])
         self.pc = (self.pc + 1) & self.addrMask
         self.excycles = 0
         self.addcycles = self.extracycles[instructCode]
diff --git a/py65/devices/mpu65c02.py b/py65/devices/mpu65c02.py
index 2ac5a9d0..ef37f74a 100644
--- a/py65/devices/mpu65c02.py
+++ b/py65/devices/mpu65c02.py
@@ -8,11 +8,11 @@ def __init__(self, *args, **kwargs):
         self.name = '65C02'
         self.waiting = False
 
-    def step(self, trace=False):
+    def step(self):
         if self.waiting:
             self.processorCycles += 1
         else:
-            mpu6502.MPU.step(self, trace)
+            mpu6502.MPU.step(self)
         return self
 
     # Make copies of the lists