info-mac@uw-beaver (info-mac) (11/16/84)
From: George Schnurle <GFS@SU-AI.ARPA> My Mac died last week. It would clear the screen, put up a dead Mac, and give the error code 040800. Well, the 04 means a ram error, and Bill Croft said the 0800 meant ram "11". I took the Mac apart and lo and behold, there were no indications of which ram was number "11". So, I checked for continuity between the 68000 and the 16 rams and came up with the following table: Code Data Bit Ram Code Data Bit Ram * 0 F5 * 8 G5 * 1 F6 * 9 G6 * 2 F7 * 10 G7 * 3 F8 0800 11 G8 * 4 F9 * 12 G9 * 5 F10 * 13 G10 * 6 F11 * 14 G11 * 7 F12 * 15 G12 I replaced the ram at G8 and my Mac is back. I put a socket in just case I ever decide to get Fat. If someone would like to add the error sub-codes to this table and resend it, we would have all the necessary info in one place. The following was sent to INFO-MAC from ERIK at SRI: The codes under the Sad Mac correspond to a class code (2 hex digits) and sub-codes. The class codes are: 01= Rom Test Failed (subcodes meaningless) 02= Memtest (bus subtest) (subcodes correspond to bad RAM chips) 03= Memtest (bytewrite) (") 04= Memtest (mod3test) (") 05= Memtest (addr. uniqueness) (") 0F= Exception: subcodes: 0001 = Bus error 0002 = address error 0003 = illegal instruction 0004 = zero divide 0005 = check instruction 0006 = trapv instruction 0007 = privilege violation 0008 = trace 0009 = line 1010 000A = line 1111 000B = other exceptions 000C = ? 000D = NMI