Make sure you changed the socket wiring to be compatable with the new ballast, some 3-wire electronic ballast will require only one wire to each lamp at one end (two reds) and one wire to both of the other ends (yellow wire), while some require other wiring changes, if the ballast was wired wrong it can take out the electronic ballast they are not very forgiving, also on the 6 wire ballast make sure the ears are not shorted, that when disconnected from the ballast you should not have continuty between the red set, (red to red) blue set or yellow set of wires, with the lamps removed, about the only other thing is the lamps, never use a F-96 T-8 lamp on a T-12 ballast, as they dont have the heaters in the ends of the lamp and will short out the 6-wire HO T-12 ballast, T-8 lamps are lit by HF current 20 Khz, and only have electrodes for the end contacts.