X31 fuzzy screen problem

[icebag]

I have recently put together a working X31 from two faulty machines. For the most part it is working very well. It's currently my favourite TP.

However it does have a problem that I haven't come across before.

When it is running on battery, if I plug in the power lead the screen goes fuzzy. The fuzziness lasts a minute or two and then it clears gradually and returns to normal. (While the screen is fuzzy the machine is still working.)

Plugging in the power lead also causes the internal wifi to disconnect and I need to tell it to reconnect.

Have the techie sleuths out there any idea what the problem might be?