Be sure that both ballasts have their ground wires attached to the fixture frame with an electrically sound connection. For the second ballast I drill a hole in the frame and scrape the white paint away from the hole to expose bare metal. I then use a pop rivet with matching washers to secure the new ground wire to the frame. Be sure that no bare hot wires can touch the fixture frame. I use crimp connectors, although the screw-on connectors are good enough if you screw them on properly.

I'm not sure the problem is with your fixture, however. It could be that the first bulb simply burned out and that the second bulb was defective to start with.

The electronic ballasts are sensitive to electrical surges. I protect mine with surge protector plug-in strips. Once I plugged an overdriven fixture directly into a wall socket and the contacts weren't made simultaneously, causing a surge, and the ballast itself was fried. Since then I use surge protectors that have their own on/off rocker switches.

MM

What exactly do you mean by smoked. If it smoked at the lampholder, then that means there was an arc, thus causing that type of ballast to stop. Make sure the tube is in complete contact with it.

-j-