Welcome.
The very first thing you need to do is open up the headbox and identify every board - what it does and where it is located.
The second thing you need to do is make sure the backup battery is chopped off the MPU board OR chop it off yourself - RIGHT NOW!
This battery is the single most common 'killer' of the MPU (main computer board) in these machines.
If you are in doubt take some pics, put them up here and there will be plenty of members able and willing to help.
