I have an autotransformer for a lamp that immediately, and without being connected to the bulb, starts to hum and smoke when connected to the socket. When i connect the bulb, the bulb lights up, but the tranformer continues to smoke. As pictured, the transformer takes either 220V or 125V, and steps it down to 125 V @ 300W. Does anybody have any advice in what's the best course of action for troubleshooting and repairing the transformer? As you can probably gather, i have very little experience and knowledge in electronics repair, but i am tying to learn and i do have access to the maker space at my university where i believe i can access the tools and materials i need to troubleshoot and repair the transformer.