I have posted a problem in the Linux forum., but I have not received any recommendation for a repair shop in Chiang mai which can fix a problem with a Linux system (all that I have asked have been Windows only). I am posting here to get local knowledge.

I saw the issue you are experiencing.... It is not an easy one to diagnose, as it most likely means you have missing drivers somewhere. You could have very well done something which corrupted a specific driver on your latest session... Only a very professional technician would be able to diagnose, find the missing driving, and repair your current installation. 

Most other technicians, are just gonna boot a Linux distro through a USB, back-up your stuff, reinstall your Linux distro from scratch, put all your stuff back and call it a day. 

You might as well try to do that yourself, they're gonna charge you (probably a lot) for something which you can DIY. Remember, someone who is professional enough to diagnose your issue won't be working at some random computer repair shop.... So all they're gonna do is repair (and perhaps they're lazy and even lose some of your data, so you know.....)

ctxa is correct, in that you are better off with DIY.

If you really want to try an investigation first, I'm happy to take a look at it, if you fancy visiting (10km south of city center).

Be Fixed in Mae Chok Plaza.  I just had some work done on a computer and was talking to the owner.  He runs Linux.  Excellent English.  Nice guy.  It might be worth a call.

Thanks to all who replied, I have now found a fix and can cancel the request.