If it looks right, plug it in.
That's what happened when someone plug in a 300mA wall plug into a 7" tablet expecting 5V 2A.
I measured the DC out and got 7V. The battery (4V) also got 7V. So, most of the electronics are fried.
But the interesting thing is that the LCD screen come up for a few seconds complaining a low battery condition. So, some thing is still working.
The question is why didn't the wall plug failed open circuit, but end up driving over-voltage. Isn't that unusual?