You will have to take your keyboard down there, but they will recycle it if it cannot be mended. They take all computer equipment, working or not. Any that can be made to work is refurbished and sold at low rates to community project. This produces enough money to recycle the useless bits (yes it cost money, because of the labour involved in dismantling)
By the way it is quite hard to find - although listed as Brandon St, they are actually in the row of shops which face Rodney Road on a first floor level walkway accessed by steps from Brandon St or via a ramp from the junction of Larcom St and Rodney Road.