I recently purchased a used TI-83 Plus and got it in the mail just a few days ago. It's in pretty good condition; all of the rubber feet are there, and it's not too badly scratched up. However, when pressing on the lower left side of the calculator, there's a very annoying creaking sound. I initially thought maybe the plastic clips that held the shell together had come loose, but they all seemed to be fine.

Is this how it's supposed to be from the factory or is my calculator actually damaged? If it's the latter, is there anything I can do to fix it? Maybe the screws aren't tight enough or something.

Any help would be appreciated.

I can say that they aren't normally creaky - but there is definitely a possibility that things have loosened over time. Do you have the ability to open it up to have a look?