* During shipping, it is possible that a lamp was damaged. Sometimes, the cracks may be so tiny that you cannot see them, but they allow the gases to escape. The lamp will not light. Contact the company you purchased the lamp from for their policy on freight damage.
* A certain percentage of lamps (from any manufacturer) will not light. This failure is not common, approximately less that 5%. Contact your lamp distributor for information on replacements.
* Make sure that the lamp ends are properly installed in the lamp-holder. They may be loose and not making proper connection.
* Replace starter (if your unit uses them).
* Check your lampholder to see if any are black, melted, or have a loose wire. Replace if needed. See our lampholder FAQ for more information.
* If you have followed all instructions above, you probably have a failed ballast. Replace the ballast. See our ballast FAQ section for more information.