I recently bought a new notebook; the HP Spectre x360, a 13” convertible ultra-slim notebook PC. It is a really nice piece of hardware, chiselled from solid aluminium with great battery life, decent performance and a pretty usable keyboard.
When the laptop is folded back it automatically converts to tablet mode, wherein the keyboard is automatically turned off so that the keys are not accidentally pressed while using the touchscreen interface.
But since I bought it I have found that, on booting up the device in laptop mode, with it sitting open on my desk, the keyboard is mistakenly turned off. No amount of opening and closing the screen will trick the keyboard into coming on, and it is necessary to log in using the touchscreen interface and on-screen keyboard. After lots of opening and closing it seemed that eventually the keyboard would come back on but there seemed to be no logic to the problem at all.
This post on the official HP forum describes a similar problem. Unfortunately the HP rep simply assumes a hardware fault in the hinges and advises the owner to send it back for repair. However, once my keyboard is on, the connection stays on even as I adjust the screen angle, so it seems a hinge connection failure is not the issue here.
Finally, after much confusion, I found the answer: When the laptop is rotated sideways it attempts to switch to tablet mode, even when I have not adjusted the screen angle. The sensing it done by an orientation sensor in the base of the laptop, not in the hinges! I have found that, to turn the keyboard back on and to go to laptop mode I can tilt the whole laptop towards me slightly, and voila! So far it has worked every time. I wish that there had been some way for me to find this answer out earlier!