Just for fun, it would be interesting to compare +3.3V (RG2 tab) between the working and failing RasPis. I get 3.29V on the working pi (an RS model FWIW) which seems reasonable, and ~2.55v on the unhappy one. Does USB work before RasPi dies? If not, the LAN9512 USB hub/Ethernet could be the culprit...

Hi forum dwellers, My Son's Pi has started failing, and I thought I'd ask here before contacting Farnell for an RMA. When power is applied, the CPU/RAM, regulator (RG3) and F3 get blisteringly hot within 30 seconds or so, and then the pi shuts down. Before it shuts down, the boot process appears to ...