Sad Mac Error Codes

TITLEMacintosh: "Sad Mac" Error Code Meaning
Article ID: 7748
Created: 7/2/91
Modified: 9/9/97
TOPICWhen I turn on my Macintosh, I get a black screen with a "sad Macintosh" face and the numbers 020016. There is no listing for this error code in any of my manuals. What does it mean?
DISCUSSIONThe particular error code that appears with the "sad Macintosh" is not as important as WHEN it occurs. If the Macintosh can start up from a different system diskette, then the problem is probably with the system software on the other disk. System problems are usually identified when you get a "happy Macintosh" face and the "Welcome to Macintosh" screen before the "sad Macintosh."

If the "sad Macintosh" face appears immediately at power up, that usually suggests an issue with the logic board or memory. Try starting up from a floppy disk before assuming it's a hardware problem.

Sad Mac Error Codes Description

On the Original ROMs (Macintosh 128k, 512k, 512ke, Plus):

When you press the interrupt button on the side of your Macintosh when starting up, you should get a sad Mac icon with '0F000D' and some bits cycling under the icon indicating it is performing a memory test.

This numeric code is in two parts:

  • The first two characters are the class code. The class code tells what part of the diagnostic program found the error.
  • The second four are the sub code. The sub class code tells what the error was. In the case of a bad RAM chip, the sub class identifies the bad chip (this was very helpful to homegrown upgraders).
Class CodeSub Code
1 = ROM test failedMeaningless
2 = Memory test - bus subtestidentifies bad chips
3 = Memory test - byte writeidentifies bad chips
4 = Memory test - Mod3 testidentifies bad chips
5 = Memory test - address uniquenessidentifies bad chips

Single Chip Identification
Data BitLocationSub Code Bits
0F50001
1F60002
2F70004
3F80008
4F90010
5F100020
6F110040
7F120080
8G50100
9G60200
10G70400
11G80800
12G91000
13G102000
14G114000
15G128000
Class CodeSub Code
F = Exception0001 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 NMI (normal indication)
0064 Couldnt Read System File into Memory

Macintosh SE & Macintosh II ROMs:

The Sad Mac error codes have been changed to incorporate additional power for testing and to support the 32-bit world. Generally, the same codes are used for 68000 exceptions as the Macintosh, however they are displayed differently.

Traditional
The traditional Macintosh error codes are displayed like this:

0F0003

Where F indicates an exception occurred, and 3 indicates an illegal instruction occurred. On the Macintosh SE and II, the display would appear:

0000000F
00000003

Note: 0000003 is a hex number.

Power On
The new power-on error codes have the following format:

XXXXYYYY
ZZZZZZZZ

Where XXXX is internal test manager state information (ignore this), YYYY contains codes that indicate either an exception code, or the test number for a power on test failure. The ZZZZZZZZ code contains additional failure information to help track down the problem.

YYYY Error Codes:
$0001The ROM checksum test failed. Ignore the Z field.
$0002The first small chunk of RAM to be tested failed. The Z field indicates which RAM Bit(s) failed. This small chunk of RAM is always in Bank B.

Example:
$AABBCCDD

AA=8 bit mask for bits 31-24
BB=8 bit mask for bits 23-16
CC=8 bit mask for bits 15-8
DD=8 bit mask for bits 7-0

$0003The RAM test failed while testing bank B, after passing the chunk tested for code $0002. The Z field indicates which bits failed as in code $0002.
$0004The RAM test failed while testing bank A. The Z field indicates which  bits failed as in code $0002.
$0005The RAM External addressing test failed. The Z field indicates a failed address line.
$0006Unable to properly address the VIA1 chip. The Z field is not applicable.
$0007Unable to properly address the VIA2 chip (Macintosh II only). The Z field is not applicable.
$0008Unable to properly access the Front Desk Bus. The Z field is not applicable.
$0009Unable to properly access the MMU. The Z field is not applicable.
$000AUnable to properly access NuBus. The Z field is not applicable.
$000BUnable to properly access the SCSI Chip. The Z field is not applicable.
$000CUnable to properly access the IWM chip. The Z field is not applicable.
$000DUnable to properly access the SCC Chip. The Z field is not applicable.
$000EFailed Data Bus test. The Z field indicated the bad bit(s) as a 32-bit mask for bits 0-31. This may indicate either a bad SIMM or data bus failure.
$000FReserved for Macintosh compatibility.
$FFxxA 680xx exception occurred during power on testing.
The xx indicates the exception:
$01  Bus Error
$02  Address Error
$03  Illegal Instruction Error
$04  Zero Divide
$05  Check Instruction
$06  cpTrapCC, Trap CC, Trap V
$07  Privilege violation
$08  Trace
$09  Line A
$0A  Line F
$0B  unassigned
$0C  CP protocol violation
$0D  Format exception
$0E  Spurious interrupt
$0F  Trap 015 exception
$10  Interrupt Level 1
$11  Interrupt Level 2
$12  Interrupt Level 3
$13  Interrupt Level 4
$14  Interrupt Level 5
$15  Interrupt Level 6
$16  Interrupt Level 7
$17  FPCP bra or set on unordered condition
$18  FPCP inexact result
$19  FPCP divide by zero
$1A  FPCP underflow
$1B  FPCP operand error
$1C  FPCP overflow
$1D  FPCP signalling NAN
$1E  PMMU configuration
$1F  PMMU illegal operation
$20  PMMU access level violation
Macintosh Portable ROMs:
The bootup code in the Macintosh Portable contains a series of startup tests that are run to ensure that the fundamental operations of the machine are working properly. If any of those tests fail, a Sad Mac icon appears on the screen with a code below that describes what failure occurred. Here is a typical example of a Sad Mac display with an error code below it:

SAD MAC CODE

05460203   =   (D7.L)

000OB6DB   =   (D6.L)

The two codes are actually the contents of the two CPU data registers D6 and D7. The upper word (upper 4 hex digits, in this case 0546) of D7 contains miscellaneous flags that are used by the start-up test routines and are unimportant to just about everybody except a few test engineers within Apple. The lower word of D7 is the major error code. The major error code identifies the general area the test routines were in when a failure occurred. D6 is the minor error and usually contains additional information about the failure, something like a failed bit mask.

SAD MAC CODE BROKEN DOWN

Test Flags    Major Error

 0546          0203

Minor Error   Minor Error

0000          B6DB

The major error is further broken into the upper byte that contains the number of any 68000 exception that occurred ($00 meaning that no exception occurred), and the lower byte that usually contains the test that was being run at the time of failure. If an unexpected exception occurred during aparticular test, then the exception number is logically ORed into the major error code. This way both the exception that occurred as well as the test that was running can be decoded from the major error code:

SAD MAC CODE FURTHER BROKEN DOWN

68000 Exception    Test Code

02                  03

In this example, the code says that an address error exception ($0200) occurred during the RAM test for Bank A ($03); $0200 ORed with $03 = $0203.

Major Error Codes
Below is a brief description of the various test codes that might appear in the major error code:

**Warning**: Some of these codes may mean slightly different things in Macintosh models other than the Macintosh Portable. These descriptions describe specifically how they are used in the Macintosh Portable.
$01 - ROM test failed. Minor error code is $FFFF, means nothing.
$02 - RAM test failed. Minor error code indicates which RAM bits failed.
$05 - RAM external addressing test failed. Minor error code indicates a failed address line.
$06 - Unable to properly access the VIA 1 chip during VIA initialization. Minor error code not applicable.
$08 - Data bus test at location eight bytes off of top of memory failed. Minor error code indicates the bad bits as a 16bit mask for bits 1500. This may indicate either a bad RAM chip or data bus failure.
$0B - Unable to properly access the SCSI chip. Minor error code not applicable.
$0C - Unable to properly access the IWM (or SWIM) chip. Minor error not applicable.
$0D - Not applicable to Macintosh Portable. Unable to properly access the SCC chip.

Minor error code not applicable.

$0E - Data bus test at location $0 failed. Minor error code indicates the bad bits as a 16bit mask for bits 1500. This may indicate either a bad RAM chip or data bus failure.
$10 - Video RAM test failed. Minor error code indicates which RAM bits failed.
$11 - Video RAM addressing test failed. Minor error code contains the following:

upper word           =       failed address (16-bit)

msb of lower word    =       data written    

lsb of lower word    =       data read


Data value written also indicates which address line is being actively tested.

$12 - Deleted
$13 - Deleted
$14 - Power Manager processor was unable to turn on all the power to the board. This may have been due to a communication problem with the Power Manager. If so, the minor error code contains a Power Manager error code, explained in the next section.
$15 - Power Manager failed its self-test. Minor error code contains the following:

msw  = error status of transmission to power manager.

lsw  = Power Manager self-test results (0 means it passed, non-zero means it failed)

$16 - A failure occurred while trying to size and configure the RAM.

Minor error code not applicable.

Minor error codes Power Manager Processor Failures

If a communication problem occurs during communication with the Power Manager, the following error codes will appear somewhere in the minor error code (usually in the lower half of the code, but not always):

$CD38   Power Manager was never ready to start handshake.

$CD37   Timed out waiting for reply to initial handshake.

$CD36   During a send, Power Manager did not start a handshake.

$CD35   During a send, Power Manager did not finish a handshake.

$CD34   During a receive, Power Manager did not start a handshake.

$CD33   During a receive, Power Manager did not finish a handshake.

Diagnostic Code Summary

Below is a summarized version of the Sad Mac error codes:

Test Codes

      $01     ROM checksum test.

      $02     RAM test.

      $05     RAM addressing test.

      $06     VIA 1 chip access.

      $08     Data bus test at top of memory.

      $0B     SCSI chip access.

      $0C     IWM (or SWIM) chip access.

      $0D     Not applicable to Macintosh Portable. SCC chip access.

      $0E     Data bus test at location $0.

      $10     Video RAM test.

      $11     Video RAM addressing test.

      $14     Power Manager board power on.  

      $15     Power Manager self-test.

      $16     RAM sizing.

Power Manager Communication Error Codes

      $CD38   Initial handshake.

      $CD37   No reply to initial handshake.

      $CD36   During send, no start of a handshake.

      $CD35   During a send, no finish of a handshake.

      $CD34   During a receive, no start of a handshake.

      $CD33   During a receive, no finish of a handshake.

CPU Exception Codes (as used by the startup tests)

      $0100   Bus error exception code

      $0200   Address error exception code

      $0300   Illegal error exception code

      $0400   Zero divide error exception code

      $0500   Check inst error exception code

      $0600   cpTrapcc,Trapcc,TrapV exception code

      $0700   Privilege violation exception code

      $0800   Trace exception code

      $0900   Line A exception code

      $0A00   Line F exception code

      $0B00   Unassigned exception code

      $0C00   CP protocol violation

      $0D00   Format exception

      $0E00   Spurious interrupt exception code

      $0F00   Trap inst exception code

      $1000   Interrupt level 1

      $1100   Interrupt level 2

      $1200   Interrupt level 3

      $1300   Interrupt level 4

      $1400   Interrupt level 5

      $1500   Interrupt level 6

      $1600   Interrupt level 7