I used to visit harajuku a few times a week many years ago , never visited that store. It’s well hidden though Tokyo is like that , stores hidden away through small corridors and lifts.
I did visit one similar many many years ago but I think it was in akihabara , I wasn’t buying synths back then though. I remember stacks of nord gear.
Must be so much easier now that iPhones / android phones can do so much. Most of my time in Tokyo was before smart phones ( though Japanese had powerful flip phones ).
We had 2megapixel cameras and were often asked not to take pictures.
BTW, if you are visiting the store and are hungry, on the floor below (3rd I think) there’s an awesome TINY little restauraunt that sells noodles and fried chicken. If you come out the lift it’s the one on the right.
A super-hip little no-nonsense eatery with even cooler clientelle sitting eating, smoking and having beers with their food.