Need help with SportDog 400 Collar

[Minnieski]

Hi!

My trainer seems to think that using an e-collar will help with some of the issues I'm having with Tanner lately. Fortunately for me, a family member gave me their old SportDog 400. However, I can't get it to work. I've fully charged it, and both the receiver and the transmitter appear to be on, but no signal seems to be sent/received when I push any of the buttons (tone, nick, or continuous). The light does come on on the transmitter. I was thinking that it might be the batteries, as it was uncharged for about 2 years. But as both seem to be on, maybe it's a connectivity problem? Thoughts? I don't want to spend $60 on new batteries and have it still not working.