I had the same problem with the same board. the sm1 is faulty, i desoldered it, and tested with xgpro using because it is same pinout as 27C1000A. You can also read it and save it into your hard drive and compare it with the sm1.sm1 file inside the neogeo.zip with another software as hxd hex editor. if you use a socket it is a good way to proceed.