Laser working disc won't spin

My console came with the ring of death, got my money back, and i decided aftewards work on it. I replaced the disc drive, after deep cleaning, disc hard worked fine with cd, not with games, thats when i found out i had to replace the mother board. After replacement, console works fine, i can play live, tray open and closes, although some times when i move it roughly (because i am still figuring out how to fix it) the ring of death comes back, i have to unplug everything inside, plug again and it once again works fine. Anyway, after i did the motherboard replacement, disc won't spin, any DVD or cd! Laser seems to be fine. The moment i turn the console on it flashes twice, once cd its on it flashes and makes some noises, it last few seconds, then it asks to open tray. Ive tried to use the multimeter to maybe calibrate the laser but i just couldn't get the reading right. So, despite the fact now have a better console than i first got i am still trying figure out whats wrong. Any ideas?