thanks for your help. I swapped out the LM2576-5 and the circuit came back to life.
what would cause a LM2576-5 to go bad like that?
joan wrote:Have you considered using a pair of BECs, one to convert to 12V and one to 5V? They only cost a few UK£ and may be more efficient.
eBay search for 5V and 12V BEC.