it should see that its not a battery pack (or rechargeable AA's) and is non rechargeable AA battery's and not attempt to charge it, but i am not for sure on that model.

i know that on a MP 2100 it wont attempt to charge battery's using the AA battery tray, it has to be a battery pack before it will attempt to charge it. so on this model you can have it plugged with it having standard AA battery's in the battery tray and be fine.

but like i said i know almost nothing about your model of newton to give you a correct answer