Thanks for this - it's solved the other problem which made the Vox unusable.
I accept oldyellr's comment about cheap chargers, but I travel light through countries with UK 3-pin and EU, USA and Australian 2-pin. Carrying an adapter and individual chargers is a pain, particularly since my original Vox charger is a bulky UK one. It's much less bulky to carry a single, small, locale-specific charger with a USB A female slot, and use cables to charge phone, tablet, Kindle, GPS etc.
So finally, 18 months after buying it, I've got a tablet which I could travel with. Except that it's now underpowered and I gave up and bought something else