Why Does My Bionaire Shut Off A Few Seconds After Turning On Ionizer F

I bought a Bionaire BAP600 *USED*. (I know, I know!) The air filtering works fine, so does the night light. But if I turn on the (optional) ionizer feature, the whole unit shuts off within a few seconds. Not a huge loss as I got it super cheap, just wondering if anyone else has experienced this problem. If so... any tips for fixing it? (Besides buying a new one! :)

Thanks!