Crock Pot Ham and Potatoes

6-8 pieces pre cooked ham, cubed or thinly sliced
8 potatoes peeled and sliced thin
1 onion sliced
1 c grated cheese
1 can cr of mushroom soup

Toss sliced potatoes in 1/2 tsp cream of tarter and one cup water. Drain. Put half of ham, potatoes and oinion in corck pot. Sprinkle with cheese, repeat with remaining half. Pour undiluted soup over the top and cook on high for 4 hours or until done