Sudden workbee fault issue

Hi there, been using my workbee for a couple of years now, when suddenly it stopped, 99% of the way through a job. Whenever I now try to power the duet from the power supply, all the limit switches LEDs, as well as the green and red LEDs along the edge, flash over and over.

If I connect my laptop over YAT with the power supply turned off, the device behaves normally and I can see the web interface, and everything reports fine in YAT, so I have no idea what these flashing LEDs could mean, and can’t find any mention of this in the documentation. Any ideas?

Cheers