Personal IRIS 4D/20 error LED meanings


Challenge L
Nov 23, 2019
I've been trying to revive a Personal IRIS 4D/20 that I got not too long ago. I did a PSU replacement on it and now that the power is good it seems to start up but it hits some sort of selfdiag error. The four red LEDs on the back of the Emodule turn on, then the bottom one turns off for a bit and then turns on again.

I've seen this table for the error LEDs

*ooo - DUART test failed
**oo - Walking bit memory test failed
***o - Memory address uniqueness test failed
**** - Graphics test failed
*o*o - Interrupt mask test failed

Assuming that the * represents on LEDs and the o represents one that's off, this would seem to suggest the issue is either the "memory address uniqueness test" or some sort of a graphics issue. Interestingly enough my old ViewSonic monitor seems to be getting some form of video signal out of the graphics, although the output is just black. So maybe there's a sync signal or something coming through. I didn't see anything on serial either but I think it might be wired wrong.

What counts for a "memory address uniqueness test"? Why does it swap between the two different LED outputs?

Anyone have any ideas?


Storybook / Retired, ex-staff
Feb 4, 2019
Mountain West (US)
From my understanding a "memory address uniqueness test" (in general, not specific to the 4D) relates to setting unique values in the various cells and trying to read them back, ensuring that reading/writing from the cells yields the expected address.

It may fail to do so due to stuck or non-operable bits on either the address or data lines. If the address lines are broken you will get back the value expected from another memory location. If the data lines are broken you will get back an incorrect value for every location.

Sync and a (probably blank) video signal might be generated by the graphics card RAMDAC even if other parts of it or the system are broken, as long as it gets some sort of initialization.


Challenge L
Nov 23, 2019
I went and dug out a PC with a physical serial port and just plugged it in using a straight through cable. Serial comes up fine using 9600 8N1 XON/XOFF

Serial comes up fine, all diag tests pass except the graphics subsystem.


It seems that it needs a keyboard attached possibly for the GR1.1 based board to actually give a video output? Kaigan tested booting his Personal IRIS with a GR1.2 for me without a keyboard attached and it gives those same error messages, except it brings up the PROM and prints them to the screen.

printenv also seems to think that the keyboard not being attached is the issue, as the "gfx" variable is set to "dead (No keyboard)"

I have a ps/2 to SGI keyboard converter here so I'll probably go build a keyboard cable to rewire the converter to the 9 pin Dsub keyboard port.

About us

  • Silicon Graphics User Group (SGUG) is a community for users, developers, and admirers of Silicon Graphics (SGI) products. We aim to be a friendly hobbyist community for discussing all aspects of SGIs, including use, software development, the IRIX Operating System, and troubleshooting, as well as facilitating hardware exchange.

User Menu