China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

While most problems with fluorescent lighting is fixed by changing the bulb, another problem can be lurking that requires a little more knowledge and skill to repair. If the fixture fails to light after all of the bulbs have been replaced, the culprit most likely will turn out to be the fluorescent ballast.

Ballast replacement presents the possibility of exposure to potentially hazardous voltages and should be performed only by qualified personnel. All installation,inspection and maintenance should be performed only with the entire circuit power to fixture or equipment turned off. Installation shall be in accordance with National Electric Code.
Before you spend time replacing the ballast on your fluorescent light, make sure that the light bulb is not about to die. The lights will give this away by flickering. A dying bulb also may display black bands on the ends. If a new bulb still flickers, glows at the end or hums, you have to replace the ballast. This part of the bulb regulates the electrical current to the light.

Start the job by removing the old ballast.To access the ballast, start by removing the cover to light fixture.

After the cover is removed, you should be able to see the ballast.You will need to remove the plugs from the fixture before removing the ballast.Lay out the ballast and plugs on a counter or table top that has some work space.You will notice that there are three sets of two wires with each pair being the same color.Move the old ballast out of the way and lay the new one in its place.Install thehigh pressure sodium ballast back inside your fixture.Fold the excess wiring into the middle of the fixture.