Keys don't work on Sub 37

Hi everyone. I’m new to the world of Moog. I bought a used Sub 37, and the bottom 5th of the keyboard doesn’t work – all 8 keys do nothing. It doesn’t matter if I’m using a preset or shift octaves. All the other keys work fine. I’m sorry if this is a noob question, but am I missing something or is this unit broken? I’ve tried hard resetting global settings, and I looked through the manual. I just wanted to check with some veterans before approaching the seller.

Thanks!

I have a Sub 37 as well and the entire keyboard should work.. sounds like its broken, I’m afraid.