I found that if you position the volume control and headphone jack on the PCB and hold it there with a little piece of blue painter's masking tape (do one of them first, then the other) in their positions and DON'T solder yet, then place the PCB in the case and test for fit with the holes in the case . . . if the fit is not good, reposition the part and secure again with the tape

As the instructions state, the small board containing the volume pot must be at right angles to the main board for a proper fit

I then soldered only 1 or 2 tabs and rechecked for proper fit and knob rotation once again

Other reviewer stated that he had to cut holes in the plastic case in order to get a good fit, that is just plain false

I used a piece of tape to hold it still while putting the circuit board into the cabinet in order to check for proper fit