hi, i have this imac A1419 emc 2834 mb: 820-00292 that is in loop and black screen. i have find dump with same number motherboard and same number emc but after reprogram it the problem got worse so i reprogram with original dump and with this machine turn on but with same problem. i think dump is not good for this imac beacause with original dump 3 led on motherboard turn on and i listen dong sound and it repeat in loop but with dump that i found just 2 led turn on so it is not compatible. can you help me please?in allegate original dump