I'm not sure what a MP5000 is... Is it a Minolta EP-5000? With a ARF-9? If it is you may have a sensor problem or it could be the two one way gears that drive the paper feed rollers in the doc feeder..... Can not be sure if that is the model you are asking about... It may also,be one of the sensors in the doc tray.. I'm also not use to A4 & A3 paper sizes.