Your brown spots could be due to drought, lack of irrigation coverage in that area, lack of moisture retention due to runoff or inadequate watering. Assuming you are located somewhere in the SE with SA. Needs water. To determine if it is chinch bugs, check the outer, greener portion of the turf as they will have moved outward to suck the juices. Look for insects about ant size with white wings. They can fly short distances to the good neighbor. If you find them treat with a liquid pesticide as granual dursban will not be watered in as required with a coverage problem. Check the sprinkler system.