Quick update on the toothbrush (I didn't think it would provoke so much discussion), it is the battery and it is 1.2V Ni-MH. This morning I set up a test with a new AA alkaline cell (1.6V) and it would not start, pop it back onto the charger base for a moment (yes I know, not supposed to charge alkaline batteries
) and if you press the power button just as you remove the brush from its base it kicks into life (extra power boost).
Once the brush has been activated, it will start each and every time you press the button, regardless almost of the battery voltage it will restart, even with the voltage dropped to as low as .9V. Therefore, it seems to have a reset system once the battery gets so low that won't restart and giving it a pulse from the charger resets it?
New battery will be ordered now and see how that goes.