pastiche,
except for the displays, is the game running normally, i.e. with the lamps flashing in an attract mode? If so, then the fuse for the displays could have blown, or one of the two display power rails (+ and - 100v) could have failed, a power supply fault. If the game isn't running, the Cpu board could be faulty, and 'blanking' the displays to prevent them getting damaged.
On the Cpu board there are two small red l.e.d.'s. When switching the m/c on, these should both blink and then go out. With the coin door open, pressing the 'diagnostic' switch on the Cpu board should cause them to each blink twice. Other results (listed in the linked manual) occur if the Cpu test detects a problem.
Incidentally, the display panels aren't Lcd, but 'gas discharge' type. I thought at first that you were asking about JJP's 'Wizard of Oz'.