My older display case has a fluorescent light fixture in it, but only has a white wire, a black wire, and two blue wires. How do I hook up a ballast and connect to a line?

Is the original ballast missing? Do you have the new ballast, of the same type?

There are wiring diagrams on each ballast.

Before you get an answer, we need to know the exact fluorescent lamp and ballast catalog number, along with the ballast, as there are probably hundreds of lamps and even more ballasts.

I am missing the original ballast. The bulb type is f30t12, and the ballast I have is a GE 140rs120-diy. It's a 3ft bulb. My display case has a space for a ballast built in to it but no red wires, so I am confused. I've blown 3 bulbs already trying to set this thing up.

It might be the wrong ballast.

$32.51 GE 140RS-120-P VALMONT BALLAST 1 FC32 OR FC40 120V ADVANCE RL14OTP (http://www.atlantalightbulbs.com/ecart/10Expand.asp?ProductCode=GE140RS-120-PVALMONT)

Here is a ballast for you: BallastWise - E-Ballast DXE130M12 (http://www.ballastwise.com/item.asp?PID=12&FID=1&level=0)

Specs:
http://www.ballastwise.com/images/upload/Documents/DXE130M12.pdf

Don't worry about the colors to the sockets, just wire the ballast exactly as the wiring diagram.