Amiga problems: screen colors and their meaning (errors)
When you boot up your Amiga you are always greeted with a series of flashing screen colors. On most days the screen will change from dark gray to a couple lighter shades then white before marching on. On bad days, it flicks over to an actual color of the rainbow, each with its own heart-stopping meaning.
What do those colors mean? And what is the Amiga doing during the boot-up process in the first place?
The following is a collection of ancient and excellent information compiled from varioussources.
During boot-up, the Amiga is going through a series of system checks and routines.
Clear all chips of old data
Disable DMA and interrupts during the selftest.
Clear the screen.
Check the hardware ….checks to see if 68000 processor is working.
Change screen color.
Do a checksum test on all ROMS.
Change screen color.
Beginning of system startup.
Check RAM at $C0000 and move SYSBASE there
Test All CHIP RAM.
Change screen color.
Check that software is being executed.
Change screen color.
Setup CHIP RAM to receive data.
Link the libraries
Check for additional memory and link it (FAST RAM)
Turn the DMA and interrupts back on.
Start a default task.
Check for 68010, 68020, 68881 or other processor upgrades (accellerator / math co processor).
Check to see if there is an exception or processor error
If so do a system reset.
During this system test the Amiga is sending vital information to the screen with colors. If the system checks out ok, you will see the following sequence that you have seen so many times.
DARK GRAY: The initial hardware tested OK. the 68000 is running and the registers are readable. LIGHT GRAY: The software is coming in and seems OK. WHITE: The initialization test have passed and the system is ready to boot.
The failure mode screen colors:
Turquoise (0x0CC) (A1000 only): RAM failure in the Kickstart WCS
Green (0x0F0) error in the lowest 256 bytes of Chip RAM. Possible causes, defective CIA-A IC or defective Agnus IC.
Yellow (0xFE5) an unexpected processor exception before the appropriate system failure message was prepared. This could mean defective hardware or an attempt to access a RAM address where no RAM exists.
Red (0xF00) invalid KickStart ROM checksum.
Magenta (0xF0F) single-task or cold-start initialization failed.
These problems could be caused by a number of things such as a loose chip or board. The red screen may be caused by a loose Kickstart chip that can be fixed by pressing down on the ROM to check it is fitted correctly. Another cause could be a connection problems between the chip and socket that can be solved by straightening an bent pins.
Alternatively, the green screen could be caused by a loose memory board, SIMM, or a loose RAM chip on the memory board. If reattaching these chips do not solve the problem, try them on another Amiga.
Another listing of screen color interpretations:
Kickstart ROM error
Two ICs in A1200, A3000, A4000
Custom chip problem
Denise Paula Agnus
Above problems combined
CIA (U7/U300) problem
CIA (U7/U300) problem
If not booting
Hardware tested OK
Software tested OK
CIA (U8/U301) problem
Stops at gray, CIA defective
ROM or CIA
R406 or R215 open R406=1 ohm R215=4.7 ohm
Agnus or Denise defective
The keyboard also has its own processor, RAM, and ROM. It also has a selftest that performed on power up in the following sequence.
Performs checksum on ROM’s
Checks 64 bytes of RAM.
The timer is tested.
Performs handshake with computer and gives results of self-test.
If the keyboard does not pass the test, it will tell you through the blinking of the caps lock light.
If the Amiga caps lock key LED blinks repeatedly at boot up, another series of error messages must be consulted:
One blink: keyboard ROM checksum error
Two blinks: RAM failure
Three blinks: watchdog timer failure
Four blinks: A short between two lines or the special control keys.
READ THIS (please). Don’t panic if your keyboard flashes once when you switch on. THIS IS PERFECTLY NORMAL. Every Amiga in the entire universe does this.
If something is wrong with your system, you may see the following:
RED: Error was found in ROMS.
GREEN: Error found in the CHIP RAM.
BLUE: Error was found in the custom chips.
YELLOW: If 68000 found an error before the error trapping software (GURU) was running.
It’s not always obvious why your Amiga guru’s. With the codes below, you can break the meaning down to its basic components and get to the bottom of things.
Probably all Amiga owners have seen the guru at one time or another. The guru meditation is what your Amiga does when the low level error trapping routines catch an error before the computer crashes. When the higher-level routines detect the error you are given a requestor saying: ‘Software Failure. Task held. Finish ALL disk activity’, with two gadgets saying retry and cancel. Retry usually does nothing and cancel causes a guru.
The proper term for the guru is an alert. The alerts give you some useful information about why the Amiga crashed and what program caused the program to crash.
FORMAT OF ALERT ERROR NUMBER: #DSGeCode.TADDRESS
D: This indicates whether or not the software failure is recoverable or not (with the current OS none are really). A zero means that it is recoverable and any non-zero value means that it isn’t.
S: This (together with D) indicates the subsystem that generated the alert. The various subsystems are (DS):
Ge: This indicates the general error. Basically telling you what went wrong. The various defined General Errors are (Ge):
01 .. No memory 02 .. Make Library 03 .. Open Library 04 .. Open Device 05 .. Open Resident 06 .. I/O Error 07 .. No Signal
Code: This gives more detail as to what went wrong. The value that appears here depends on the subsystem and general error.
TAddress: This is the Address of the task that caused the guru (where applicable).
Quite often the processor with trap an error. The operating system will then display a guru. These errors will only contain two digits (the right-most two digits in ‘Code’) and their meanings are:
00000000 Reset (SP). /Technically, these shouldn’t occur, but 00000001 Reset (PC). /they do pop up occassionally 00000002 Bus Error (memory doesn’t exist) 00000003 Address error (usually odd address access) A program probably made a jump to somewhere it shouldn’t have 00000004 Illegal instruction 00000005 Divide by zero. A program has attempted to divide a number by zero (a mathematical impossibility). 00000006 CHK instruction (Check register against boundaries) 00000007 TRAPV instruction (Trap on overflow) 00000008 Privilege violation. A program in user mode attempted to execute a privileged Instruction. 00000009 Trace (debugging) 0000000A Op Code 1010 (unimplemented instruction) 0000000B Op Code 1111 (unimplemented instruction) 0000000A & 0B A & F Line Emulation. Used with some coprocessors. Usually program is out of control. 00000018 .. Spurious interrupt. 00000019 to 1F .. Auto-Vector Interrupts – These should not happen as the OS uses them to detect what is going on with the hardware, but as with all others they do appear sometimes. 00000020 to 2F .. Trap Vectors – Usually a program is out of control. 00000030 to 3F .. These are reserved by Motorola. Any program causing these is probably out of control. 00000040 to FF .. User Interrupt Vectors – Usually a program is out of control.
If you enter a command and comes back with an error message, typing WHY will display more information about it. Use the FAULT command to display the error message that applies to a error code.
Typical error messages are:
Insufficient free store .
Free up some memory by quiting other programs
Task table full
Shutdown some programs
Argument line invalid or too long
Check command arguments using `?`
File is not an object module
Try setting ‘e’ or ‘s’ protection flag.
Invalid resident library during load
Object in use
Exit program, unassign assign or close directory windows.
Object already exists.
Cannot move the program as it exists elsewhere. Delete the original first
Directory not found
Retype directory name
Object not found
Retype file name
Invalid window description
Re-enter correct window description for NEWCLI or NEWSHELL
Packet request type unknown
Stream name component invalid
Invalid object lock
Object not of required type
Disk not validated
Wait until disk is validated first.
Ensure write tab is closed.
Rename across devices attempted
Use copy instead
Directory not empty
Must delete its contents first. Use DELETE ALL.
Device (or volume) not mounted
Check device name and reinsert disk
Check position in file
Comment too big
Use shorter description in FILENOTE
Delete some files or use a new disk.
File is protected from deletion
Enable Delete flag with Protect
File is write protected
Enable Write flag with Protect
File is read protected
Use PROTECT to set ‘r’ flag.
Not a valid DOS disk.
Disk is unformatted or a protected game disk
No disk in drive
Use correct device name or insert disk
No more entries in directory
Directory is full, delete files or move files into new sub-dirs.
(just preserving your great information, thanks for this!)
Retrocomputerverzamelaar.nl is opgericht door Angelo Houben. Verzamelaar van oude computers, bestaande uit home-, personal- en spelcomputers. De passie is ontstaan doordat hij is opgegroeid met de Commodore 128 en de verzameling begon in 2007 toen iedereen deze computers massaal dumpte, hij een Commodore 64 computer ophaalde bij een adverteerder, voor een retro middag van het werk…