Here are two different 1992 Bally Dr Who playfields.  The one on the left was made by TAG (Thomas A. Grant) in 1992 for Bally and the one the right was made by SP (Sun Process) in 1992 for Bally.  Note the color differences.  The Sun Process playfield was a higher resolution print.  Both playfields have the crappy made inserts that are found in most 1990-1992 Bally/Williams playfields.  In 1993 Bally/Williams changed their inserts to a higher quality plastic.  The inserts used in 1990-1992 (Addams Family, Black Rose, Dr Who, Funhouse, Whirlwind, Diner, T2, Fish Tales, Getaway, etc) tend to discolor and crack.  Click here for more info.