![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.
![What would be the suggested rectifier for a simple lead/acid automotive battery charger? - Electrical Engineering Stack Exchange What would be the suggested rectifier for a simple lead/acid automotive battery charger? - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/BnaUe.jpg)
What would be the suggested rectifier for a simple lead/acid automotive battery charger? - Electrical Engineering Stack Exchange
![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)