Ampeg BA-210 Quits when hot?

I bought a brand new Ampeg BA-210 last year to replace the old BA-115 that quit on me. I removed the head from the BA-115 and converted it into an auxiliary cab for the BA-210. It wasn't used until my daughter began playing on it in our band last March. It worked just fine for a few months up until our last practice and our last gig, when it just randomly decided to stop sending signal. On both occasions it was getting power and was set at about 5 on the volume knob. Once it was cooled off (although it didn't seem unusually hot) and sitting for a while it started working again and I have tried several different cables and two different basses to try and trouble shoot it, but I still have no idea why it quit on us in the middle of a song. I'm assuming it has something to do with it getting too hot, but I just don't know for sure. Any help would be greatly appreciated. Thanks.

 

Sorry, I meant BA-115 as the aux cab. Yeah, I think your right. The 115 speaker is 4Ω and the 210 aux output is 8Ω. I can't believe I missed that. Could be the problem right there.