Hello. Yesterday I bought a G610 Orion Brown keyboard. Keyboard is really nice, except one thing. When backlight is in medium state, keyboard produces buzzing noise. It's not very audible, but when it's quiet in room, a noise is annoying. There is no noise when backlight is in brightest position or is turned off. So I would like to ask is this is normal, or I should return keyboard to my local retailer?