Original post by: Reece ,
Sounds like you have the schematic and board view for this. Check out the power aliases page, check all G3H and S5 power rails whilst just the charger is plugged in (battery is probably bad if it looks really cheap). If any rails are missing, not steady or not what they should be according to the schematic, look into it. If DC in voltages are reading at 16V or over and is lighting up, the DC jack is fine. You can't get these new anymore, so it usually has flux on the PCB where a new charger port has been soldered on (probably not corrosion). Leave the SPI ROM alone for the moment, this will be fine unless it has been damaged, reprogrammed or replaced by someone else. Usually if this is bad, the fan will spin but it won't chime, very rare for it to be dead from a bad SPI ROM (also, they rarely corrupt without cause). Check out main power rails and look into this further.