Unfortunately, I don't get much time lately for my music hobby! Any time I have available is being spent on site maintenance and redeveloping my Technics sites for a re-launch.
However, I've been reading your thread. This sounds to me as though the ribbon cable connecting the cover is failing. I think you should stop using it and find an engineer before it gets worse as you open and close the lid. Failure of these cables due to age and repetitive opening and closing of the lid has been on JD5live's mind I know because we have discussed it often.
I think the error 83 is probably a red herring and is to do with a file that the keyboard can't read correctly from your SD card. I have some info about error 83 but haven't been able to find it yet with a quick search.
I hope it is something simple to fix!