Yes, the battery is a type 523 4.5v. It's the one in the attached photo. I got it from Amazon: http://www.amazon.com/gp/product/B005AW9YGE/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1. I know the battery is good because I checked it with a voltmeter.

I'll have to take a close look at those contacts.  If that seems fine, is there anywhere else that I should Iook?

Thanks for the suggestions.