Broken top screen potentiometer

I’ve replaced the SD Card/Trigger assembly and was having some problems with the screen. I managed to fix it by tweaking the potentiometer yesterday, but today it was all messed up again. I took the battery cover off and realized the screw for the top screen potentiometer was missing. I still have the old, working part and the DSi works fine when the SD card assembly is unplugged. Is there any way to bypass/fix it? Buying a new part isn’t an option because it’ll be more profitable to buy a new system entirely.