Fixing an Overloaded Ryobi One+ Battery Charger

Was working on electrical stuff with a friend - who had left his battery charger plugged into the circuits he was messing with. Also, some idiot had previously used a white wire as a hot wire, and didn't identify it with tape or anything. So this charger got zapped with 240 volts. It made a little 'pop' but that was it. Sorry, I didn't have the foresight to record the diagnosis. That proceeded as follows: Smell test - does it smell crispy? No Visual test - does it look crispy? No Check fuses - good Check for voltage going through varistors - check Check for voltage going through diodes/bridge rectifier - check Check for voltage entering transformer - fail! Part replaced: TOP256EN