i believe the problem is the failsafe unit in the cube. The clicking noise you hear is from the relay witch give power to the blades. As a part of a safety mechanism this failsafe "unit" is sensing the current to the fan, so if the fan stop the current will change and the relay click off due to not overheating the blades. You can try this to either change fan or simply to block a part of the fanoutlet with a piece of cardboard so you hear th fan is changing speed and sound. i think you then will get a different , longer, shorter "uptime" from your cube. A bad way to solve the problem is to bypass the failsafe circuit to bridge  the two terminals of the relay. This is the worst way to solve the problem and  beware of overheating.!!