I have two M7270s (haven't checked to see if either one works, yet - need a working chassis with an 18-bit backplane, too lazy/busy to pull the removable terminations on my working Sigma Q22). One has: 1611H 21-16890-00 3007D 23-007B5-00 3010D 23-008B5-00 2007C 23-003C4-00 which is fairly different from yours; the date codes range from 8018 to 8021 on the uROMs, and 8029 on the ALU. 1611H 21-16890-00 3007D 23-007B5-00 3010D 23-001B5 2007C 23-002C4-00 which is intermediate between yours, and my first one (but does seem to indicate that to some degree, these things could be mixed, they aren't matched sets). The date codes from the ROMs are 8026, 8041 and 8126, and 8031 on the ALU (so the 002 2007C is later than the 003...) Noel