Your question presumes that the flyback is dead, but you don't seem to have done any testing at all to verify that this is in fact the case. So to ask about "reviving" it is a bit premature. Many things can cause loss of video. Maybe your flyback is dead, but do a little testing first before you flail about.

First, your video disappeared during or after you took things apart. In my experience, the most likely cause of a problem is the one doing the disassembly. Carefully check over your work. Common errors include things like cables left unconnected or cables connected improperly (e.g., off by one pin, or backwards, or a pin bent). Verify that the crt's connector is in place securely (it's easy to bump). And if you happened to have bumped it hard and heard the "hiss of death" then your problem is a bad crt.

If you have a small neon bulb handy (like the type often packaged in cheap "pen" type electrical testers sold for a dollar or two in grocery stores), you can check for the presence of high voltage (and therefore, test the flyback indirectly). Just hold it near the high voltage lead (do not disconnect the high voltage lead). The strong ac field in the vicinity of the wire is sufficient to excite the neon atoms if HV is present.

Needless to say, performing that test requires you to work on a powered-up, exposed-guts Mac, so use caution. We don't want to lose any Forum members!