Does anyone know the calibration procedure for a My Weigh 3001T digital scale? I'm getting an error message that it's out of calibration, but I don't have a manual and can't find one online. There is a "CAL" switch on the bottom, but I'm not sure what to do after putting it in calibration mode. I'd at least like to try to get it working again before I throw it away and get a new scale. Thanks.