Sounds like the TILT coil has shorted.

The TILT relay isnt necessary on Bally EM's, but if it is locked on TILT, it will override everything. Try moving the TILT mech to unlatch the leaf switches if you havent done so already. Also make sure you have credits on the game.

Dont know if you have this info, but from Clays site - bally start up sequence....

Bally Start-Up Sequence.

Coin is inserted into the game. The coin relay will energize. It will stay energized through its own hold-in switch and a score motor switch. If the credit button is pressed (instead of a coin being inserted) and there are credits, the credit relay will be energized which energizes the coin relay.
The coin relay will energize the lock relay (this turns the general illumination on). The lock relay will stay energized through its own hold-in switch and a delay relay switch.
The coin relay will energize the reset relay, through a game over relay switch (if your game won't start, try cleaning the contacts on the game over relay; a very common Bally problem).
The score motor will operate. This will energize the score reset relay(s). The score reset relay(s) will attempt to clear the score reels to zero. This is done by operating the score motor. Each turn of the score motor will operate the reset relay once, which in turns moves a score reel one position, until the score reel(s) are at zero. If the score motor continues to run when a game is started, there's a good chance the zero position switch on the score reel(s) is dirty or mis-adjusted.
The coin relay, through the score motor, will advance the total play meter.
The reset relay, through the score motor, will reset the stepper units (zero the ball count and player units).
The coin relay, through the score motor, will decrement the credit unit.
The coin relay, through the score motor, will energize the game over latch relay coil.
The coin relay, through the score motor, will energize the 100,000 relay latch coil(s) (if the game supports scores greater than 99,999).
If the outhole switch is closed (single ball games) or the ball trough switches are closed (multi-ball games), a ball is released to the shooter lane through the outhole relay (single ball game) or ball release relay (multi-ball game) and the score motor.
On multi-player games, the credit button may be pushed again to add a player. This time the coin relay will not energize the reset relay. Instead it will (through the score motor) advance the total play meter, decrement the credit unit, and advance the coin unit.