Too Many Indigos
Well, the Silicon Graphics Indigo Workstation project is just about a wrap. As these things go this was (and remains to be) a challenging restore. But man, what a cool little computer. It was one of my favorites back in the day and I wrote a reasonable amount of code on one back at NASA.
The R4000 Indigo with Elan Graphics
It started with finding a plastic shell in perfect condition (they are almost always trashed) on eBay. I didn’t know how long it would take to find a working (or mostly working) Indigo to put into it so I just bought it on faith. After several weeks an Indigo R3000 (lower end) with base graphics came up on eBay for a good price. I bought it, it worked great for a few weeks then the power supply died. Being that Indigo power supplies are nearly impossible to find, I decided to hack a (rather expensive) ATX power supply to work with it. In retrospect, I should have tried to restore the old supply, it was likely a failed capacitor and simply replacing all of them probably would have fixed it, but analog stuff is not my favorite to debug, so I just went “new” and cannibalized the old supply for the special connector used to connect it to backplane.
The R3000 “mostly worked” but the Indigo’s massive 5V inrush current (34A) would trigger the protection logic on the ATX power supply and as a result I never really got it boot reliably. Once started it was fine and would restart easily for several hours, but once it sat, nope. My theory is some huge capacitor in the supply would charge when switched on. If it had completely discharged prior, tough to boot it.
In the middle of that odyssey, I met a guy with an Indigo R4000 with Elan Graphics (the top end of an Indigo’s) online. He is moving and needed to get rid of several computers (In fact an entire garage full). I thought about it for a day but that R4000 was just too good to pass up. It arrived a week later. It works fantastic and he did a lot of the things I would normally do including replacing the Hard disk with s Solid State drive. Really all I did was take it apart, clean it, change out the shell for the perfect one that I bought. It is such a nice box I actually like it more than the newer SGI Indy I restored a while back. I think it’s the form factor. And its purple. You have a love a little purple computer.
The color turned out perfect. For reference the drive bay door is in the middle of the image and is original. There was still a bit of extra sheen in the photo that I knocked down with a matt finish. Now, it’s a perfect match.
I liked it so much I did another retro-recreation LCD monitor for it matching the SGI Indigo Purple/Blue perfectly using only two different colors of paint. I think it’s my new favorite in the collection (although I’m still a Sun guy are heart) and the graphics performance is fantastic (for 1993 anyway).
Meanwhile, I still have the R3000 and two shells, one is in good condition (it came with the R4000) and one is just ok, the original R3000 shell. I thought about just parting out the R3000 and selling it on Ebay, but it has become a challenge now to get it to reliably boot. I had a theory that I could probably just run it on a +5V 34A supply (much easier to find) and not even supply the +-12V. I don’t use real hard disks so I thought the drive motors were probably the only use for 12V supply. After buying a rather cheap +5V supply on Amazon and again attaching the cable harness that I now know the pinout by heart, I powered it up and it in fact the R3000 booted up to the PROM perfectly. Two problems however. No sound, and no keyboard. Both require +-12V. After some research I found the keyboard uses old-school RS232 communication @ +-12V. So the +5V supply was only a partial victory. But emboldened by this new direction I jumped on Digikey and grabbed a new +-12V supply as there remains ample room remaining in the case.
I have no idea what I’m going to do with the R3000, if I get it running. It’s already a bit of Frankin-Indigo but I’ll cross that bridge when I get to it.