Diplomat dishwasher not cleaning the dishes properly

are you sure it is filling with enough water .

sounds like an easy choice to me .REPLACE IT

something is probably down in the drain dish washer has a disposal like system at the drain

Check the brackets that hold the top rack for any broken plastic brackets. My dishwasher was making the same noise and after noticing the broken plastic pieces I pulled out the dishwasher put it on its side removed a white panel on the bottom that is attached with two screws, removed the drain line and inside there were two plastic tabs from the broken bracket. Once those were removed the grinding noise stopped. The bracket holding the drain hose can be removed with a pair of pliers.

problem maybe
1)wash pump blockage.
2)any paricles jam the motor.

Is there a chance the dishes are moving when the machine is on? Cound the water jets(spraying the door and sides) be the cause of the noise. Is the sound insulating blanket on the outside of the machine? Try running empty on a shor cycle to help diagnose the problem.

Check for foreign objects like glass or plastic at the grinder blades. Some dis assembly will be required. See appliancepartspros.com for diagram.

if you have a torx 20, and torx 15 screw driver, you an remove the screws from the top plate of the wash motor, and underthere youll see another t15 screw converingthe "chopper" assy, sounds as if a seed, of chicken bone, perhaps apiece of glass hasgottne down there

Sound like the recycling pump i had the same problem had to buy a replacment pump from whitegoods

It could be the impeller on the motor. The impeller fits over the shaft of the motor and might have split/broken up. That funny noise is probably the shaft spinning inside the damage impeller. Fortunately the impeler is fairly inexpensive and easy to replace. I believe there are one or two parts/covers to remove that are held in by a roughly half dozen torx screws.