Samsung Chromebook Plus keyboard issue

I have a Samsung Chromebook Plus that will stay in tablet mode (i.e. keyboard and trackpad don't work) when I start it. All the touch screen and pen features work fine, I can log on using the onscreen touch keyboard. If I fold the screen back and us it in tablet mode then try to go back into laptop mode the keyboard and trackpad stay locked out. When this happens I can plug in a mouse and use it as a pointing device with no problem.

The problem is intermittant. Somtimes when I've used it fir a while, the keyboard and trackpad come back. Every so often the keyboard and trackpad stay locked out the whole time I'm using it. Sometimes the keyboard and trsckpad will work straight away.

I'm thnking this might be a hardware issue with a cable that needs to be re-inserted or replaced. Has anyone else encountered this and/or have guidance for opening the chromebook and checking the cable?