My HP 694c hangs while printing

My HP 694c takes paper then starts printing then after few lines it stops and roars with noise as if something is stuck. when i try to print a test page by pressing on the test button it either prints the HP logo then stops or print half the page and stops evereytime exactly at the same point.
I took it to an agency and cleaned it well, I even changed the motherboard with another one of the HP 680 but the error is the same

i've gone mad

what could it be?? mechanism problem ?? chip problem??

is there a solution?