possibly, toothbrush chargers do vary from the very simple, with half a 50Hz transformer in the brush and the holder to the very complex with a switch mode supply in the holster that generates a square-ish wave at a few tens of KHz, and modulates the mark to space ratio to compensate for supply variation. Most these day as are universal voltage (90 V japan, via the US at 115 to EU/UK at 230, and a few things stretch to include 277 as well - one of the odder US standards.)

But it is quite possible to have an SMPSU that does not enjoy lower voltages at the input and as it draws higher current to compensate for lower inputs that puts the active devices under thermal stress. If the brush charges OK on another holster that is probably what has happened.

Mike.

Righto, thanks.

I was wondering about the 60 Hz as I've also plugged mine into the wrong holes in a shaver socket with no ill effect.

Righto, thanks.

I was wondering about the 60 Hz as I've also plugged mine into the wrong holes in a shaver socket with no ill effect.