[iansmith]

Hello, I have two SGI Iris Indigo XS 24 machines that I bought 20 years ago and have sat since then.

The problem is that when I got them, the little 8-pin DIPs that stored some kind of serial number were missing.  Buyer claimed they must have fallen out in shipping, but they wouldn't boot without them so I just boxed them and forgot about them until I moved back here recently and found them in storage.

My question is, does anyone know what these are and how to replace them?  I vaguely recall being told they were either EEPROMS or small 8-bit Microcontrollers and that you could program them with the serial/id number from the disk drives.  I do have one working set of drives, the System and Option drive.  The drive in the other box never spun up, even when I first bought it.

I am not sure if either of the boxes are operational. They power on, I get a green light on the front and even a beep but nothing after that.  I've tried to hook up the serial port to get to the console but get nothing.  Not sure if the cable I have is correct, it's a Belkin F2V088-06.  

I also have a video cable and with a 13W3 to VGA adapter adapter, but get nothing out of that either. But I have no idea what kind of signal it would be putting out anyway.

Also available to me is a Sun keyboard which I assume is compatible, I hope?  I have Ethernet transceivers as well so can net boot it if it can. That's how I got my Sun Sparc's running.

Anyone have any suggestions? Will these things give me any kind of console or video output without that chip, or do I need to find one of them first?

[Raion]

"The problem is that when I got them, the little 8-pin DIPs that stored some kind of serial number were missing. Buyer claimed they must have fallen out in shipping, but they wouldn't boot without them so I just boxed them and forgot about them until I moved back here recently and found them in storage."

Yeah whomever did this to you is grifter. DIP socket things don't just fall out.

I am afraid I don't know too much about the IRIS Indigo myself, but I wanted to welcome you to the forums anyways. Welcome, and I am sure someone here will be able to assist you with this question!

[robespierre]

The Indigo requires a SGI specific keyboard, 9500801 or 041-0136-001, and mouse, 9150800 or 041-0141-001. Sun peripherals are not compatible. Neither are Sun 13W3 adapters!
There is a solution to convert PS2 keyboard+mouse to the SGI port, which was unique to the Indigo, Onyx, and 4D/35. (Another for USB keyboard+mouse).

The chip is a 93C56 serial EEPROM, it stores the Ethernet MAC address of the machine. You should be able to initialize a blank chip from a R3000 Indigo; the R4000 CPU lacks a way to do that.

Without the chip, the machine will complain about not being able to set the clock and refuse to boot. But it will at least display that message.

[Raion]

The SGI video signal is usually Sync-On-Green, with no H/V sync sent over other pins. A sun connector requires a compatible monitor, you need a Dell or Asus, or AOC (those are brands I've confirmed tend to work) monitor with SoG capability.

The serial cable is the same as a mac printer port cable - that will work with another SGI of similar vintage or you can make a DIN8 to DB9 cable:

https://allpinouts.org/pinouts/connector...din-8-pin/

[iansmith]

Without the chip, the machine will complain about not being able to set the clock and refuse to boot. But it will at least display that message.

Thanks for the info, so before ordering a chip I should be able to verify the machines are functioning by getting data from the serial output. That is very good to know.

The serial cable is the same as a mac printer port cable - that will work with another SGI of similar vintage or you can make a DIN8 to DB9 cable:

What signal lines does the SGI require? Will it work with just GND/TX/RX? I'm trying to figure out what is going on with the cable I have, it's wired like this according to my multimeter...

DIN8 DB25

1 DTR 4 RTS
2 CTS 5 CTS
3 TXD 2 TXD
4 GND 7 SGND
5 RXD 3 RXD
6 RTS N/C
7 CD 1+7 GND
8 GND 1+7 GND

Which does not match any diagrams I can find for that cable, and I can't find any official Belkin docs on it.

Page 2 of http://www.pumpkininc.com/content/doc/guide/ag-2.pdf doesn't match what my cable is doing.

I see that my cable is a MODEM cable but you mentioned PRINTER cable. Those are wired differently I assume?

Thanks for all the help so far.

[Raion]

yes, a mac printer cable is wired differently. It's a DIN8 to DIN8

And you IME need all lines to be connected for reliability. That's my experience.

[iansmith]

yes, a mac printer cable is wired differently. It's a DIN8 to DIN8

And you IME need all lines to be connected for reliability. That's my experience.

Thanks. Do you happen to know a source for the printer cables? I've been looking, but ebay is pretty unreliable, I see "Printer cable" in the description then photos of the product say modem cable.  Hard to tell what I'm getting.  Are they the same as serial cables for the Sun workstations?

I'm tempted to try and re-wire my cable but some of the lines are tied together and I'm not sure where I'd need to undo those.

[Raion]

I don't know, as I'm not a classic mac user. but that's what mine was made from (I didn't make it myself)