lawrence@encore.UUCP (Scott Lawrence) (09/17/85)
Well, that which we all fear happened to me Saturday -
I got up and turned on my Mac and got a "dead mac"
icon with a number under it. I know from prior experience
that this means take it to my freindly Apple dealer and
be prepared to spend some money, but it occured to me that
_someone_ must know what that number means ( It isn't the
same as last time ). I wasn't on usenet last time, and my
dealer wouldn't give me the list - does anyone out there have
a list of what these codes are ? It won't really help, but
I would like to know ( this time it's 041000 ).
--
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Scott Lawrence
UUCP: {decvax,allegra,linus,ihnp4}!encore!lawrence
garym@telesoft.UUCP (Gary Morris @shine) (09/20/85)
[this line provided at no extra charge for line eaters everywhere] In article <227@encore.UUCP> lawrence@encore.UUCP (Scott Lawrence) writes: >I got up and turned on my Mac and got a "dead mac" >icon with a number under it. ... >I would like to know ( this time it's 041000 ). Scott, You have a bad memory chip at position G9 on the main logic board. If you're handy with and have a high quality soldering iron you could replace the chip yourself for under $5. If you take it a dealer they will replace the main logic board for $137.28 (that's what it cost me). That happened to me before I knew what the error codes meant. If I had known then, I would have replaced the chip. Dr. Dobbs Journal, January, 1985 had an article "Fatten Your Mac" on pg. 18 that gave complete instructions for performing a 512k upgrade yourself, it also gave a good description of the power on diagnostics performed by the ROM which I will summarize here. -- GaryM [General disclaimer: This posting is in no way related to my employer.] ------------------- Before starting diagnostics, you must have the programmers switch installed on the left side of the Mac. Hold down the Interrupt button (rear button) and then press Reset button or power on Mac. A sad Mac icon appears with a numeric code under it. If all is OK then the code is 0F 000D, and some bits will cycle under the code to indicate that the memory test program is running. The numeric code has two parts; for example 0F is the class code and 000D is the sub code (see tables). The class code tells what part of the diagnostic program found the error and the sub code tells what the error was. Each of the sixteen bits in the sub code identifies one of the sixteen memory chips (class codes 2-5 only). If the diagnostics find more than one bad chip, the sub code displays multiple bits. For example if bit 3 is bad, the diagnostics display sub code 0008. If both bit 3 and bit 10 are bad, the sub code would be 0408. If the diagnostics find a bad chip you'll have to replace it or find the problem on the board. Diagnostic Codes (Table I) Class Code Sub Code ---------- -------- 1 = ROM test failed Meaningless 2 = Memory test - bus subtest Identifies bad chips (see Table II) 3 = Memory test - byte write Identifies bad chips " 4 = Memory test - Mod3 test Identifies bad chips " 5 = Mem test - addr uniqueness Identifies bad chips " F = Exception Identifies exception cause (see Table III) Chip Identification (Table II) Data Bit Location Sub Code Bits -------- -------- ------------- 0 F5 0001 1 F6 0002 2 F7 0004 3 F8 0008 4 F9 0010 5 F10 0020 6 F11 0040 7 F12 0080 8 G5 0100 9 G6 0200 10 G7 0400 11 G8 0800 12 G9 1000 13 G10 2000 14 G11 4000 15 G12 8000 Exception Sub Codes (Table III) Code Reason ---- ------------- 0001 Bus error 0002 Address error 0003 Illegal instruction 0004 Zero divide 0005 Check instruction 0006 Traps instruction 0007 Privilege violation 0008 Trace 0009 Line 1010 000A Line 1111 000B Other exception 000C Nothing 000D Normal Indication -- GARY A. MORRIS -- TeleSoft, San Diego, CA (619) 457-2700 (UUCP) ...{decvax,ucbvax}!sdcsvax!telesoft!garym "Always listen to experts. They'll tell you what can't be done and why. Then do it." -- Lazarus Long
flip@osu-cgrg.UUCP (Flip Phillips) (09/21/85)
> I would like to know ( this time it's 041000 ). > -- *** REPLACE THIS sad mac WITH YOUR fist *** according to the 'sad mac icon' publication of 10/83 (which might not be right): the number 04 1000 points to two things. the '04' says it failed an 'initial diagnostic'. The test in question is the 'Mod3Test'. '1000' points to the bad chip. the chip in question would be chip 12. shouldnt ba a problem to fix it yourself. flip