That means something with the harddrive,either the harddrive itself is corrupted or the ribbon cable to it is not properly attached /crooked or the black clamping bar is up

I got a hold of an ipod 5th/5.5 video 80gb thick, i want to do a dual sd card hdd, everything worked fine before i opened it, after installing the sd card adapter , i decided i wanted a slim back and mod the frame to fit 6th gen faceplate and click wheel modded to fit a 5th, after everything was ready to go, before i closed it up i tried to turn it on but nothing just a blank screen, tried plugging into laptop still nothind, tried a hard reset and nothing, thought battery might be the issue, tried several batteries even brand new one's and nothing, the battery cable connector is not broken or pulled of the board. So then l tried putting back all the original components back on original harddrive original, backplate with hold cable, original battery, still nothing, wonder if messing with the click wheel did something? But still should power on even if click wheel not even connected? Any ideas?