Transient noise on AC lines

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http://forum.allaboutcircuits.com – Hi, I am trying to filter transient noise that is on the AC lines. I have a 120Vac to 24Vac transformer that goes to an LM2596 5V switching regulator which then powers my microcontroller and LCD, etc. I plug the transformer into the same power strip as a fan or other AC motor. When I switch ON or OFF the AC fan or motor, I get lots of transient noise into the system. I am mainly using SPI to communicate between ICs. I have tried TVS diodes across the 24Vac lines as well as across the 5V lines. I have tried zener diodes between 5V and GND. I have tried ferrites, inductors, LC f (Embedded)