APC BackUPS XS 1300VA made a loud popping sound after first plugging in

[Anonymous user]

I just bought a new BackUPS XS 1300VA a couple days ago. I hooked up the battery and plugged it into the wall, and subsequently turned the unit on. It almost immediately made a loud popping sound, similar to the sound of a balloon popping. I played with the menu button and looking at the LCD screen, it seems like it still works, however I'm reluctant to connect any components into it. Should I be concerned, and should I be bringing the unit back to the retailer for exchange?

Thanks.