So recently I managed to acquire myself an S-100 system for relatively cheap (but still fairly pricey to me). Now I've wanted an S-100 system for a very long time, but due to their cost and most of them being located in America, I considered this a pipe dream. So of course when one became available to me I snapped it right up without any consideration, consider it an early christmas present.
So what did I acquire? A Tei Processor Terminal (either 208 or 408, the jury is still out) all the way from Houston in Texas, how did it get across the pond? Who knows! It has been converted to run on 220v and seems to work fine on 240v so there must have been someone importing these.
If you search for information on this computer you'll probably find that image being used, and for good reason, it's one of very few that exist. It turns out Tei, although seemingly fairly well regarded in the industry at the time, is relatively obscure today. Although they talked about being founded in the late 60s in some of their adverts they seem to crop up in 1977 and by the end of 1982 they're gone.
They boast about manufacturing 'Sophisticated electronics' for over ten years before they emerged into the S100 computing scene and seemingly all interaction with them went through CMC Marketing, whoever that is. In 1981 they had a crack at making a Minicomputer (or Macrocomputer as they inexplicably call it)
All was not well, as the company seems to have fallen apart the year after the System 48 came about, seemingly a victim of the 'infinite growth forever' mindset that killed so many computing businesses in the era. I wonder if any of them are still out there...But lets go back to the beginning, or the beginning as far as we know it, the family began with the MCS 112 and MCS 122 line of enclosures for S100 Systems containing allegedly the first 8080 processor card to run at 5MHZ. These systems contained a CVT (constant voltage transformer) which later became a Tei signature. The mainframe systems were optioned with numerous cards from Tei such as the aforementioned 8080, a Z80, a few different RAM cards and a Analog/Digital card to name a few. These systems established the template for later systems.
en came the Processor terminals, first was the PT 112 and 312, built from a lot of the same components as the mainframe systems but not requiring an external floppy drive or terminal, hence the name. As far as I can tell these two types of systems were released in early 1977 and late 1977 respectively. The quality of these systems is noted whenever they're mentioned, and from my system I have to agree. These came with 6 cards in them, the CPU, RAM (32k), ROM (2k) a Parallel/Serial I/O, A disk Controller and Video card, leaving 6 slots vacant for expansion. They ran their own operating system TEI DOS or CP/M.
Then in 1978 finally, along came the PT 208 and 408, they were a more compact alternative to the PT-x12 range, containing only an 8 slot backplane and a 9 inch monitor, instead of the larger 15 inch of the PT-x12 series.
This was seemingly much the same as the PT-x12 range, presumably using the same stock of Tei cards but with a larger firmware base. Supporting Super Basic and Fortran, although presumably this could also be used on earlier systems.
After the PT-x08 range Tei seemingly goes quiet, only selling pre-existing stock and slowly advertising less and less, formally featuring almost monthly in BYTE magazine with full page spreads, and decaying down to small classified listings and the barest of mentions. However the decline of the company is not what we're here to talk about today. We're here to talk about this Thing.
As you can tell it barely fits on my desk, and my desk is not a small thing. Needless to say the postie was not as happy to see me as I was to see him when he delivered it. He didn't even have a trolley and just carried it from his van which was parked somewhere out of sight.
Now this thing is in pretty nice condition, if a little rough around the edges. But let's dive into what it contains.
Sadly the original processor board is gone, having been replaced with a Ithaca Audio IA 1010, sadly the rom is missing so no TEI DOS for me :( Of all my boards, this one is in the worst state, although there doesn't appear to be anything horrible going on. This board also seems to be younger than the rest of the system, my guestimate is early 1980, although some of the chips date from 1982 the majority date from 1979.
Next we're onto the RAM, this has also been replaced at some point, or alternatively the previous two cards were requested by the customer to be installed, however as they seem to be a little younger than the other cards i'm not sure how likely this is. This is the venerable SD Expandoram, outfitted with 64k of glorious gold ceramic 4116s. I am not sure what the dead bug on the back is all about.
And now onto the juicy stuff: the first Tei card. This is the parallel/series card, in my system it's used for the keyboard and a terminal interface, making it this system's only way of communicating with the outside world. In future I'd like to have the second connector hooked up to something. Perhaps a printer. No I don't know why it's so complicated for what it does (yet)
Next it's on to the floppy disk controller,an awful lot of bodge wires on this one and some very pretty ROMS, I'll be trying to dump those as soon as I can. Seems to have provision for 8 inch drives as well as 5 1/4, which would make sense seeing as I presume the 408 option used the same boards as the 208.
And finally we're onto the video card, now this thing is a real beauty in my mind, even if it is a complete mystery to me right now. Will also be trying to dump the 2758 in the corner at some point, even though i think it is just a character ROM.
And that brings us to the end of the boards I have, in future I would perhaps like to expand the system a little bit, but that's way down the line (just like me owning an S100 system). As a bonus here's some shots I couldn't work into this post.
All the metal has this kind of frosted finish on it which I think is kind of cool, I wonder why they did that. Especially as, as far as I can tell, all Tei cases are made in house.
After that I checked the large capacitors weren't shorted and were within acceptable range. That was all in order so it was time to power the thing up! I was greeted by a non functional -16v rail. Upon further inspection the fuse for that rail was blown and there were some burnt traces on the PSU, yikes! That's not good! Before fixing the supply I decided to investigate all my cards for shorts and found one on the parallel/serial card. Hopefully it's just a tantalum. Wish the seller hadn't fired it up.
After that I checked the large capacitors weren't shorted and were within acceptable range. That was all in order so it was time to power the thing up! I was greeted by a non functional -16v rail. Upon further inspection the fuse for that rail was blown and there were some burnt traces on the PSU, yikes! That's not good! Before fixing the supply I decided to investigate all my cards for shorts and found one on the parallel/serial card. Hopefully it's just a tantalum. Wish the seller hadn't fired it up.
After I was sure the short wasn't elsewhere it was time to fix the PSU, a few trace repairs later and I had healthy voltages on all rails! Yipee!
Unfortunately that's all I've had time for so far. So what's next? Well I've got a short to locate and a lot of reading to do to get myself up to speed. I also need to dig into the keyboard as at first glance it seems to have a lot going on. For now that's all I have for you folks.
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