EMX slight "pop" after being switched on for about

[LamptonWorm]

Hi,

I've got an EMX-1 (Smart Media, not SD) and I've noticed a pop come from either the unit or the power adapter roughly 15-20 minutes after being switched on (it isn't always at the same time, so it's hard to re-produce it exactly).

Everything appears to be working, power pack gets hot after an hour but guess that is normal, I'm using the EMX-1 plugged into a 6-way extension btw.

I wondered if any sparky people here had any thoughts on the pop? It isn't very loud, and I only found it by accident, thought I was imagining it at first but it's getting more consistent, not sure if I should worry or not..

Cheers,
LW.