In my previous post I wrote about my experience with the raspberry Pi 2B not playing the same HD and UHD videos as the old Pi model B.
A little experimenting with USB chargers (power supplies), three of them 2 Amp brand name (Samsung) and two generic 2 Amp, confirmed that the problem was definitely not in the power supply. And the Pi was playing up with all of them.
On an impulse I acquired a Laser brand USB charger/power supply with twin 2.4 Volt outputs. The Pi 2B is at last playing most - but still not all of my very large file size, very high resolution videos.
My conclusion has to be that I received a slightly faulty raspberry Pi 2B.