Retrofit ceiling fan light - bypass ballast

I'm trying to change my ceiling fan light over from a fluorescent light to a standard screw socket light since a replacement ballast isn't made anymore. However, there are 4 wires that go into the existing ballast. What are the extra 2 wires for? I was expecting a black wire and a white wire only. What are the brown (ground?) and orange wires for? Thanks in advance. Attachment 42445 (http://www.doityourself.com/forum/attachments/electrical-ac-dc/42445-retrofit-ceiling-fan-light-bypass-ballast-20141127_111902.jpg)