"The box isn't needing fixed, if you are getting aircraft on the grid, the box is working, if it wasn't there would be no aircraft on the grid."
Wrong Alan, when my RB went down, I was still getting planes at 5-15 miles, it's as though a heavy attenuator's been switched in - like your hearing aid's been turned off!
Send the RB back to W&S PLC for repair, usually a 10 day turn around.
HTH