There is a bridge rectifier visible in the lower left of the first pic.
A DC power supply will work through that for the time being, until the diodes fry completely and you are left with an open circuit.
You can buy a universal 18v plug-in power supply that will handle all the transformer and DC conversion duties. Harbor Freight sells one for about $25 that comes with a free crappy cordless drill. Just cut the plug off, and solder the leads onto the board after the bridge rectifier.