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