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The Amiga system performs the following tests at boot:

  • Step 1 - Delays beginning the tests a fraction of a second to allow the hardware to stabilize.
  • Step 2 - Jumps to ROM code in diagnostic card (if found)
  • Step 3 - Disables and clears all DMA and interrupts.
  • Step 4 - Turns on the screen.
  • Step 5 - Checks the general hardware configuration.
If the screen remains a light gray colors and the tests continue, the hardware is OK. If an error occurs, the system halts.
  • Step 6 - Performs checksum test on ROMs.
If the system fails the ROM test, the screen display turns red and the system halts.
Sequence for all main Amiga models

Almost all Amiga models present the same color sequence when turned on:

Black screen, dark gray, light gray color screens filling all monitor screen in a rapid sequence
(Amigas taken up usually 2, or at least max 3 seconds to turn on and boot).

 Amiga Color Screens Scheme

  • Red = Bad ROM
  • Yellow = CPU Exception Before Bootstrap Code is Loaded
  • Green = Bad Chip RAM or fail of Agnus Chip (check seating of Agnus)
  • Black = No CPU
  • White = Expansion passed test successfully
  • Grey = CPU Passed
  • Constant White = Failure of CPU

 Amiga Keyboard LED error signals

The keyboards of historical Amiga models are not proprietary as it happened in early computer ages, but more pragmatically it was based on international standard ANSI/ISO 8859-1. The keyboard itself was an intelligent device and had its own processor and 4 kilobytes of RAM for keeping a buffer of the sequence of keys that were being pressed, thus can communicate with the user if a fault is found by flashing its main LED in sequence:

  • One Blink = ROM Checksum failure
  • Two Blinks = RAM test failed
  • Three Blinks = Watchdog timer failed
  • Four Blinks = A shortcut exists between two row lines or one of the seven special keys (not implemented)
Please note: that the capslock 'blinks' are short in duration (about one second) and that your screen colors may falsely indicate a problem when you do a 'warm' boot depending on what state the Amiga was in before the warm boot. Its best to watch for these diagostic errors upon initial startup. If your Amiga exhibits any of these errors frequently, you should take it to an Authorised Service Center for service. The most common error you will encounter is that you'll see a bright green screen at the initial boot..this usually indicates that an addon RAM board is not seated in its socket properly. Try reseating it before you take it all to your dealer. You may save yourself some money;)

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