Back in the late 80's, early 90's, a friend of mine bought some used PDP-11/70's from Illinois Bell. He'd sell them as parts into the aftermarket and did okay. Not great but steady.

He kept one in his detached garage that would load the initial bootstrap and then prompt the console for the operating system, which he didn't have. From that point on it patiently waited for a response and was used to heat the garage.