KDS-17A is a good machine. It appears from the photo, that the outside filter ring is missing. Would be hard to fish out a spoon, etc. from that area if it fell down there as the entrance to the pump is a deep well with narrow sides!
there isnt a filter ring on the 17a since it uses what was called the SaniGuard filter. What your seeing is the stainless steel mesh filter on top and there is a plastic filter below that and a tray and course filter below that to strain out the large objects. That is to protect the pump. I know this because I had a KDD67 that had the same racks and wash system and the filter you see on the pics. To remove all you have to do is lift the wash arm and then pull the filter straight out. there are plastic clips on the inside that lock the filter in place. Very rarely did I ever have anything fall into that area except for large food particles like corn and peas and they would almost always land on the tray at the bottom near the course strainer.
Mike