Same thing happened to me. Red/Green blinking. Attempted to have a look at things myself to see if it was an easy fix. Ended up cracking one of the inner discs due to the super strong magnet (the one attached directly to the motor). And to make to complete the comedy of errors, promptly did the exact same thing to one of my others. Thus with one stroke I went down from 3 MP40ws to 1. "the guy" who bought the pumps for me with my initial setup said that he no longer had the receipt but he would take care of it by ordering a new disc........
I was looking to buy a 4th one for my system anyway, so I went out a bought another one from my local store so I would have at least 2 running while I was waiting for the parts to the other 2. After installing and running the brand new one for 10 minutes I got the blinking green/red again! arrrrrg. I checked the dry motor alone to make sure the problem wasn't with the propeller. It wasn't. The motor alone doesn't spin. Well, it starts to spin for a split second when I plug/unplug it, then stops and blinks green/red. Is there any way to fix this myself? or do I have to send my brand new pump which I have owned for less than a day away. All help is greatly appreciated.
In the mean time I bought 2