When Michael Jordan first retired from basketball in 1993-94
he rejoined the Bulls in 1995 and led them to three additional
championships in 1996, 1997, and 1998...
Jordan retired for a second time in 1999, but returned for two more
NBA seasons from 2001 to 2003 [...] Despite his January 1999 claim that he was "99.9% certain" that he would never play another NBA game, in the summer of 2001 Jordan expressed interest in making another comeback
Therefore coming out of retirement, you are said to rejoin the workforce; to return to work, or if you are a particularly well-known or famous in your field, making a comeback.
For a machine that was no longer being used you could say, it is back in working order. TFD
From The Portland Daily Sun
Monument Square Clock back in working order
Time is no longer standing still for the Monument Square Clock. The hands of time are
moving once again at the historic clock, which was installed in
Monument Square in 1975, after the Portland Rotary Club stepped
forward to raise the money needed to repair and restore the timepiece.
The Portland Rotary Club showed off the newly renovated Monument
Square Clock on Thursday and presented Mayor Michael Brennan with a
key to the clock.