If you have a service manual, spend the time to read the functional description while following along in the schematics.
My starting point was smoke and lots of it. I'm going to be busy for a while replacing every tantalum capacitor and all of the A1-A5 HV caps because one of them had arced to a wet tantalum that spewed sulfuric acid. Once that was repaired, each power-up after that, would fail because another tantalum cap had failed and burned up a resistor. Therefore, not they're all getting replaced.
DaveH52