imac 233 tries to start, but crackles and dies

[ritoru]

My mother in law's imac (bondi blue, 233 mhz, tray loading CD, RagePro) will not start up. After hearing the normal start up chimes, it sort of crackles and then dies. Sounds like a mini lightning strike. I have zapped the PRAM and reset the PMU on the motherboard. (That last maneuver was quite the challenge!) Result remains the same. I suspect something like the power supply or the CRT. But maybe the problem is as simple as a battery. I just do not know because I do not know how to trouble shoot this one. How do I determine what the problem might be? Any ideas would be appreciated. Hey, it might even keep my good relationship with my mother in law going!

[Buzz]

Does the monitor blink when the crackling occurs?

Honestly, the best bet is to take the machine to an authorized Mac dealer for diagnosis.

[ritoru]

No, the monitor does not blink. I was hoping I could trouble shoot and fix this without taking the old unit into an authorized mac dealer. But maybe that is too optimistic.