Why dont you just plug a bass into the 10 band, turn the two lowest sliders all the way up, slap the low E string and see if you blow your speaker?
There are all kinds of things that will prevent you from hearing those freqs, especially since 31 and 62 are below the fundamental of the low E on a guitar. If you turn the lowest slider all the way up you should hear at least a little bit of difference with heavy chord digging and palm mutes. Do anything on your guitar that sounds like a kick drum, and make sure you have the low EQ on your amp turned up. As long as you are not using 6 or 8 inch speakers, you should hear something change.
You probably cannot work on this eq pedal yourself, I was told (by a person who mods MXR's for pay) that the MXR EQ uses some type of monolithic construction inside, similar to the monolithic crap all the old Alesis toy mixers were using. If that's true, I would think either all the sliders would work or all the sliders would fail, not just one or two of them.
So somebody believes he can get his guitar to play 1hz? I have a 98 Ford Ranger for sale, mint condition.....best car ever made, great bargain. Call me.