identify the fault

8:30am and opening up a network extension box to see why it's stopped working.

Seems that one of the capacitors has expired.

Local electronics shop doesn't stock them, so it was eBay to the rescue.

A couple of days later, through the wonders of grace, the capacitors in each were replaced and the devices working again.

I was utterly amazed.

£1.87 > £37 for replacement devices... Even if they only last a few months! And repairing > replacing for sure.