I found the light on a timer not working so on investigation it looks like my arcadia ProT5 39W is no longer working. I have changed the bulb with a new spare D3 and checked power cable and changed the plug fuse! Still no light so .......any ideas on what else to check please? The reptile shop has offered I take both my bulbs in and they will check they work in their units. It is looking like a new light unit purchase but thought I would check.