stewart

hi just got a new jester desk for new school building. The dimmers of the lights are working properly and wiring seems to be fine but i can't seem to be able to get the desk to work. The onlt way i can get it to send a signal to the dimmers is to have the first three channels up full. if i take any of them down it cuts the lights. I know it is something stupid, have rung the supplier and he dont know. Any one help?