Technicalknockout

Hello everyone I've had my Atari Lynx for a while, and now it is not working. I was in the middle of playing Xybots when I decided to turn the backlight off, then back on. Now it simply won't load cartridges. I have a theory it is the batteries, but I have no way to test that. Also the Lynx I have is a Lynx II. Please help and thank you.