Universal Lighting Technologies

Appendix C: Possible Lamp and Socket Problems

Lamp Seating in Socket

  • Check for proper rotation and fit of the lamps in the sockets. The lamps must be properly seated in the sockets, with spacing between the socket and lamp small enough to assure proper contact but free enough to prevent binding.
  • Check for loose or broken sockets and dirty socket contacts.
  • Make any mechanical adjustments or corrections required, as noted during inspection.
This lamp is seated properly in the socket, with the mark on the base aligned with the center of the socket.   This lamp is hanging on one pin, obviously not seated properly.   This lamp is not rotated properly in the socket, which is indicated by the base mark being off-center from the socket.

Visual Inspection of Rapid Start Lamps

Rapid Start lamps have filaments or cathodes which must be continuously heated by the ballast. Although lamps may start if the filaments are not properly heated, excessive end-blackening of the lamp and shorter lamp life will result.

To help pinpoint the trouble in malfunctioning Rapid Start fixtures, we suggest the following procedure using Universal Lighting Technologies Circuit Testers.

Rapid Start Lamps

  • Check for blackened ends on lamp. This may be caused by improper lamp filament heating which, if not corrected, will continue to destroy lamps.

Bi-pin for 30- or 40-watt Lamps

  • End banding may occur gradually during normal lamp life.
  • Excessive end-blackening could be caused by insufficient cathode heating, which will result in shortened lamp life.

Recessed Bi-pin for 800ma or 1500ma Lamps

  • 1500ma lamps may discolor at end of lamps during operation. This is normal for this type of lamp.
  • Caution: 1500ma T12 and 800ma lamps are the same size. Be sure to use the correct lamp/ballast combination.

Visual Inspection of Slimline Lamps

For fixtures using Slimline lamps, this additional procedure should be followed:

  • Heavy lamp-end discoloration indicates approaching end of life, necessitating immediate lamp replacement.
  • Inoperative lamps should be replaced by known good lamps.
  • If the good lamp does not operate, check sockets, wiring, line voltage, polarity and grounding.
  • When the previous items appear to be correct and the lamp still does not operate properly, it may be assumed that the ballast is inoperative and should be replaced.
  • Inoperative Slimline lamps should not be left in a fixture, as the ballast will overheat and burn out prematurely.

Slimline Lamps

  • End-banding develops gradually during normal lamp life.

  • Heavy end-discoloration occurs at the end of normal lamp life.

Lamp Circuits

When troubleshooting, remember that ALL lamps in a series circuit will extinguish if one lamp should fail. Universal Lighting Technologies’ TRIAD electronic ballasts are available in parallel versions, which allow companion lamps to remain fully lighted if one lamp should fail. Consult electronic linear fluorescent literature for additional information.

If one lamp of a series circuit fails and the others remain lighted, it could indicate an internal short in the ballast. Consult Appendix A for ballast tests.

Component Substitution

Never use a ballast or lamp for other than its recommended application. Although many lamp types and ballast designs are physically interchangeable, their electrical characteristics and requirements are totally different. Always check the ballast label or manufacturers’ specifications to assure component compatibility.