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FarmerPotato

TM990 single-board modules 4-card chassis

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I've been looking at TM990 boards, like the TM990/102 CPU card. These can go into a 4-slot chassis. I've not come across a chassis on eBay. So, are chassis incredibly rare?

 

It seems it would not be too hard to manufacture a minimal, 100-pin backplane PCB, though. The schematics are in the manual.

 

 

image.png.9009631c1260c29c41c319b36c7ecace.png

 

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From TM990/510 Card Chassis. (Nov 1977)

http://bitsavers.informatik.uni-stuttgart.de/components/ti/TMS9900/tm990-100/MP332_990-5120_cardCage.pdf

 

Pins are 3.2mm (0.125") spaced.

 

 

image.thumb.png.a9c63aca2a71ce71e54d2e1d4fe8f1d4.png 

From TM990_100M_Users_Guide_Dec78.pdf  Appendix H.

http://bitsavers.informatik.uni-stuttgart.de/components/ti/TMS9900/tm990-100/TM990-100M_usersGuide.pdf

 

 

Here are example configurations I made up:

 

#1

TM990/510 4-card chassis, TM990/518 DC Power Supply

  1. TM990/100MA CPU: 9900, 9901, 9902, serial port
  2. TM990/306 Speech Module

 

#2

TM990/510 4-card chassis,  TM990/518 DC Power Supply

  1. TM990/102 CPU: 9900, 9901, 612 (memory mapper), 4500 (DRAM controller), 9902, serial port
  2. TM990/203A: up to 256K DRAM, 16K EPROM
  3. TM990/303B: floppy disk controller
  4. TM990/310: 48 I/O, 6 interrupts


(Alas, I did not look up original prices when I was at the SMU TI Archive.)

 

image.png.dd3dd29baf81531a08e3b2c3bb2dd781.png

 

 

 

image.png.bd81429dfe6b1eb63fec2033a7d3c4e2.png

 

 

image.png.ca1ea5d73298acd8d3a45da7038aa48f.png

 

Reference: "TM990 Family of Microcomputer Modules." TI Master Selection Guide (1983), p.26

http://ftp.whtech.com/datasheets and manuals/Datasheets - TI/TIMasterSelection-1983.pdf

 

See also: TM990 Series 16-bit Microcomputer Modules (1979?)

http://www.stuartconner.me.uk/tm990/scanned_docs/TM990_Series_16-bit_Microcomputer_Modules_from_Texas_Instruments_-_Bulletin.pdf

 

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Posted (edited)

I've got several boards available if you're interested, including that backplane (remanufactured), IDE interface, battery-backed 64K RAM, video & sound (all new designs). You should be able to find details on my website, or send me a PM. Never actually seen a chassis on ebay ... I only know of about 5 of them that exist.

Edited by Stuart
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I've only seen one of the 4-board chassis assemblies show up on eBay in the last 20 yeards or so. Several of the larger ones have shown up, but this one seems to be much less common in the wild.

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9 hours ago, Stuart said:

I've got several boards available if you're interested, including that backplane (remanufactured), IDE interface, battery-backed 64K RAM, video & sound (all new designs). You should be able to find details on my website, or send me a PM. Never actually seen a chassis on ebay ... I only know of about 5 of them that exist.

 

20210529_235741[1].jpg

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There is a 7-slot TM990-520 backplane on Ebay currently. Not sure if the 518 PS is adequate for that, but there's one of them on there, too.

 

Boards are common enough from various industrial automation houses, but usually very pricey. Stuart's boards are a good alternative.

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There may be more documentation on the rather vast Siemens website eco-system for the TM990 systems. There was some ~20 years ago, anyway.

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1 hour ago, Stuart said:

 

20210529_235741[1].jpg

Thanks! I’m not trying to build a system… yet… but your boards sound like the way to go. 

 

one question: does your backplane use the original power connector/supply or something else?

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Posted (edited)
22 minutes ago, FarmerPotato said:

Thanks! I’m not trying to build a system… yet… but your boards sound like the way to go. 

 

one question: does your backplane use the original power connector/supply or something else?

I designed the board as per the original, but I use an ATX PSU extension cable modified with ring terminal connectors fitted to the +/-12V and +5V wires and bolt these to the terminal areas on the backplane.

 

tm990_510_back.gif

Edited by Stuart
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12 hours ago, jbdigriz said:

There is a 7-slot TM990-520 backplane on Ebay currently.

 

Doh. 8-slot. Boy that 1st shot of caffeine in the morning does wonder.

 

A 99xxx-based T-bus CPU board might be an interesting project.

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On 7/10/2021 at 3:55 AM, jbdigriz said:

Doh. 8-slot. Boy that 1st shot of caffeine in the morning does wonder.

 

A 99xxx-based T-bus CPU board might be an interesting project.

I couldn't find scanned manuals for CPUs other than the TM990/100M board. Appendix F is the schematics.

 

The TM990/103 board is a 99110. So the schematic would be in the user guide? If that manual could be found. 

 

Though it should be right in @Stuart's wheelhouse to create a new 99105 board 🙂

 

 

 

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I have a few random 990 manuals around here. I'll have to look to see if any of what I do have hasn't been scanned yet.

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3 hours ago, FarmerPotato said:

I couldn't find scanned manuals for CPUs other than the TM990/100M board. Appendix F is the schematics.

 

The TM990/103 board is a 99110. So the schematic would be in the user guide? If that manual could be found. 

 

Though it should be right in @Stuart's wheelhouse to create a new 99105 board 🙂

 

 

 

Aha! I knew I had seen a reference to such a board somewhere. https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1654474

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3 hours ago, Ksarul said:

I have a few random 990 manuals around here. I'll have to look to see if any of what I do have hasn't been scanned yet.

Great!

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There is a original TM990 power supply I can pick up locally. I just don’t know what I would do with it. Bring it to a future fest to trade? 


Texas Instruments TM990/518A Low Voltage Power Supply For TM990 Microcomputers.
 

I am guessing that I might find legacy 990 things given that DSEG was based in Austin TX. Just not sure what I would do with bits of TM990 and that AT clone TI 955 monster.
 

I’m currently going for TI Omni printers—I absolutely loved the 132-column Omni 800 I got as a junker in the 80s. It ran solidly for a long time. .
 

a while ago, I passed one up on Craigslist that was retired from duty after printing wide forms for 20 years. Free. Still wish I’d gone to get it. 

 

So I’m getting this 80-column TI Omni 800 model 855 which was supposed to combine daisy wheel AND dot matrix. excited about reprinting my game manual! (Though stuff looked good laser-printed, using  retro Elite mono space font with  Apple Pages. But that feels like cheating.)

 

 

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