The LED on generic chargers should still light and voltage measured at the DC/output charger plug even when it's not connected to the battery.
Beyond the fuse in the plug, there's often a low value fuse (typically 3A) inside the charger, sometimes soldered to the board. If you can open the charger, I'd check that first and if okay look to see/smell if there's any burn marks/component failure. It depends what type of charger it is, but they're often not worth fixing.