Is this the original DX7S in the JR case? If so, I think they were NiCad batteries. SR batteries can put a pack together for anything with the correct connectors. There are still a few of these radios flying at our field and seem to work fine. They have the older, more to difficult programming but if you are not doing anything complicated, these were great radios. But as someone suggested, would not hurt to send back to Horizon Hobby to get checked out. They have always been reasonable cost wise for me

bob