Xperia Tablet not vibrating

logic board seems dead i.e. steady mag safe light on disk spinning , black (dead ) screen ,pram won't reset , power management wont reset either . Vidia chip has a bad connection ! it needs heating up to reflow the pins connecting it to the logic board . check posts on this subject . It is a bit of a long shot but IT CAN BE FIXED (i have managed to do it ). i also let it heat up and soak tested it for 24 hrs after the baking trick ,blow torch (small iroda 50-70 watt Maplins )+clamping it down when as hot as possible. the only question is reliability !!It has lasted 3 months so far, and that is being thrashed non stop until red hot over and over again . It is still a bit of a guessing game (not like the old days of soldering a cct board with a dry joint ) with no cct or wiring diagrams . i would like to know the details of the electrical connections as in many cases of a 'dry joint' if you are not a 100% sure of which pin/connector that has caused the problem , one cannot be sure its fixed as it might be a...