Because one of our members popped into the chatroom and left before i could answer, i thought it might be a good idea to post these here.
Amiga boot error code coloursWhen the Amiga boots, if it encounters a hardware fault the system will display a solid single coloured screen, or a series of these screens if more than one error is detected.
The following colours are valid for all versions of AmigaDOS since Kickstart 1.3. However, there were several more colours in 1.3 compared to anything included after Kickstart 2.0 was released. However all of the colours listed below are the same for all versions of Amiga kickstart.
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Red - An error in the Kickstart rom as detected.
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Green - An error in the Chip Ram was detected.
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Blue - An error in the custom chip set was detected.
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Yellow - The CPU encountered an error before the system's error-trapping code (the code the calls up the Guru) was in place.
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Black - No CPU detected.
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Grey - CPU Passed the test.
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White - CPU failure.
In addition to colour screen error codes, Guru Meditation error screens are also a common error screen encountered when an Amiga encounters a problem. These and the meaning behind their error codes will be covered soon.
Keyboard Blink CodesWhen the Amiga is first switched on the keyboard might blink a number of times to indicate one of the following errors.
* One Blink = ROM Checksum failure
* Two Blinks = RAM test failed
* Three Blinks = Watchdog timer failed
* Four Blinks = A short exists between two row lines or one of the seven special keys (not implemented)
Source:
http://wiki.classicamiga.com/Amiga_boot_error_code_colours