So I've got a decent battery charger that handles agm, standard and gel car batteries. Charges really well and works really well. I plugged it into my bronco to get it charged up since it's been sitting a while. Figured I'd let it charge the 2 red top optimas over night. Come out the next morning and the charger is dead. Just does nothing when plugged in. Figure I'll tear it apart and check things out one day. Today was that day. I open it up and start checking things. Circuit boards look good, circuit breaker is good and transformer looks good. I then start checking resistances. Check the resisters on the circuit boards and the transformer. All checks good. Just when I'm about to give up I decide to check the cord coming in. Black wire is open. So I go in my other garage and cut the cord off my old dead drill press. Plug it in to the charger and it still won't work. So I check that cord. It's open on the black wire too! I test an extension cord and find it is good so I cut it and plug it into the charger. The charger comes to life and works perfectly. So I go in my other garage with another cut extension cord and hook it up to the old drill press. It now works too! Not sure what I'll do with 2 floor standing still presses and a bench drill press too but I'm happy they all work now. Charger is currently back to work charging my bronco.

Before tossing something it may be worth your time to check the cord. I've never seen this before so to have it on 2 things is pretty odd.

That is odd.