Do you hear the fan in the Zivan come on? If not, probably a blown fuse in the charger.
It’s a really weird size fuse, hard to find. Also, depending on when the charger was produced, you might need to do some soldering. Here’s an old thread with some info on fuses
Somewhere I read on here an old post from @GEMmechanic or @Old_Houseboater (I forget whom) where that stated they had about a 50% chance that after you change the fuse in a Zivan, that it won’t just blow it again immediately, indicating that it’s done for.
If you want change chargers, think about if you ever want to upgrade to lithium before you buy a charger - that way you get one that can work for both your current batteries and lithium packs.