I see, maybe it's different on the first gen DX7? I don't have a DX7s.
I'm not going to open it to find out though as it works perfectly for the past 2 years now?
I'm not going to lose my sleep over it too, but it is not done properly from the safety point of view. The bare pins carrying mains voltage protrude from the back of the PCB and are within 2mm of the case. Fortunately there are no vents, so your kids wont be able to drop a penny inside.