Soundcraft vI600 issues

vI600 (upgraded vi6) has issues with bay control card, stays black until it decides to "christmas tree" and then begins to function. It also has an issue with static crackling sounds coming from the masters and center channels, but coming from where? who knows. no sound source on channel, no signal reflected in metering monitor, just static crackle blast that is AFL (after fader layer). Static crackle sound only appears when channel is assigned to an input source (stagebox or local rack). solution unknown, but will not be elusive for too much longer. Ill post videos of how it was repaired once solution realized. If you have ideas, let me know.