2-There is a capacitor connected to the filament, in many cases the capacitor was short CCT this was the only fault. Replace the capacitor removed fault Voila, CFL is back to life. 3-CFLs with blown fuse, It was mainly caused by a fault in DC bridge cct., I simply replaced all the rectifying diodes (I have tons of them in my lab) and voila, rebirth of another CFL. 4-Another common fault in the CFLs was Short 400V capacitor that I assume had caused damaged to the transistors and resistors connected to them. There was no sign of resistor color codes as they were to dark ( I assume caused by overheat) but I had plenty of similar CFLs in hand and I checked the one with good resistors, Their value of the first resistor was around 2 ohms and the other around 20 ohms. I also had to change the transistors as well. Another CFL brought back to life. 5-Diac and its 500Kohm resistor at fault .In a few cases, I found the 500Kohm resistor to be open cct. ,And in some cases changing the diac itself resolved the fault....
Try this: 1-press home and power button at the same time for about 10 sec. 2-keep the power button pressed and and release the home button. 3-release the home button after you see the apple icon on display. 4-Write back in here the result so we can help more if needed.
Simran is right.However do not panic.Your system is not effected as long as you are on AC power.Just keep the power adapter connected .that's all.Change the battery at your first convenient