Macintosh: "Sad Macintosh" Error Code Meaning

The "sad Macintosh" icon and its associated error codes exist only in older Macintosh computers. Newer models, such as those with Universal Serial Bus (USB) or Open Firmware, use a different mechanism for reporting such failures. For more information on newer systems, please see the following articles:

Article 58183: "Power-On Self-Test Beep Definition - Part 1"
Article 58442: "Power-On Self-Test Beep Definition - Part 2"
Article 95036: "Power Mac G4: Power-On Self Test"

Overview

The 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 disk then the fault is probably with the system software on the other disk. System faults are usually identified when you get a "happy Macintosh" face and the "Welcome to Macintosh" screen before the "sad Macintosh."

If the "sad Macintosh" appears immediately when you turn on the computer, that usually suggests an issue with the logic board or memory. Try starting up from a floppy disk before assuming it is a hardware fault.

Sad Mac Error Codes Description

On the Original ROMs (Macintosh 128K 512kK 512kK, Plus):

When you press the interrupt button on the side of your Macintosh when starting up, a sad Mac icon on the screen 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).

The "sad Macintosh" error codes for Macintosh SE and Macintosh II computers were 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 but they are displayed differently.

Traditional

The traditional Macintosh error codes are displayed in hexadecimal notation like this: 0F0003

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

0000000F
00000003

Power On

The 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 fault.

The startup code in the Macintosh Portable contains a series of startup tests that are run to ensure that the fundamental operations of the computer are working properly. If any of those tests fail, a "sad Macintosh" 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 hexadecimal 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 a particular 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:

Important: 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.

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

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