Laptop charger is weird?

Here's a puzzler. I've been using Macs for years, so I've accumulated a small collection of wall chargers. They're all first-party Apple tech, and all of them still work - except one. or, at least, it doesn't work properly. For some reason this charger will work fine on my wife's laptop, which is exactly the same as mine, but it doesn't charge my laptop. Every other charger works just fine on my laptop.

I have no idea why this is true. It's so bizarre. Any thoughts? It's not a big deal, since I have other chargers, but any sort of answer would be appreciated. if it helps at all it's one of the older chargers with the square heads, rather than the newer chargers with the thinner cylinder.

 

Depends whether your charger that's not working for your laptop has a different voltage to your other charges.If it does, then that is the main reason. Not quite sure why that would happen. If this problem still persists, I recommend to contact Apple Support about this.

 

Are you sure you both have the same laptop? Did you buy them at the same time? Could they be different versions of the same model?