![Old style Schumacher 12v battery charger went nuts after connecting (for a while) in reverse. Need help to know where to start. Now it just hums for a few seconds, then shutdowns. Old style Schumacher 12v battery charger went nuts after connecting (for a while) in reverse. Need help to know where to start. Now it just hums for a few seconds, then shutdowns.](https://i.redd.it/3ysgksmo6le61.jpg)
Old style Schumacher 12v battery charger went nuts after connecting (for a while) in reverse. Need help to know where to start. Now it just hums for a few seconds, then shutdowns.
![Rectifier, 80 Amp Compact Negative Base Replacement for Century, Solar and Other Negative Base Chargers Rectifier, 80 Amp Compact Negative Base Replacement for Century, Solar and Other Negative Base Chargers](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/81bMo-8nEuL.jpg)
Rectifier, 80 Amp Compact Negative Base Replacement for Century, Solar and Other Negative Base Chargers
Repairing a 12v battery charger.... What the heck is this? | Electronics Forum (Circuits, Projects and Microcontrollers)
![Replacing the selenium rectifier in a vintage car battery charger - Electrical Engineering Stack Exchange Replacing the selenium rectifier in a vintage car battery charger - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/SGKQa.jpg)