The documentation on the quantum entangler is missing something. With two star-upgraded compact machines, I've tried both crafting them with the entangler, clicking/right-clicking them with the entangler, and jumping up and down on top of them while holding the entangler and yelling "ENTANGLE!!"... But as yet, nothing seems to have happened.

Suggestions?

You are correct, there are some hints missing when trying to "read" from a block that has not been used before. To do so you have to enter the machine at least once and upgrade it with a Nether Star (or whatever your config defines as the upgrade item).

I will add corresponding messages that will tell you what's wrong in the next release.

This is fixed in 1.10.