Blown Bulb Or New Casing

[julez]

Please can someone help me save a few pounds. The lights on my juwel rio240 tank have stopped working. I took them out and swopped them round I noticed one was a bit black at the end. They worked for about 15 min then stopped again if I pull plug out and put back in again they work for about 1 or 2 seconds then go off. Do I need 2 new bulbs or do I need the whole lighting bar. Any advice would help!