I have no fear to taking my machine top or bottom off to see inside. Every machine I have has screws, some hidden. The repairman has to be able to take the thing off without leaving marks. I have found almost 99% of my machine problems by just looking. Once I found a pin wedged by a gear, holding it stuck. Removed the pin and everything was fine. Never did figure out how that pin got in the machine. Once my bobbin clutch was stuck and I saw the problem by looking. You can take the top off and not be in the computer part if you have a computer machine. Don't worry about that.