VOGONS


First post, by i486_inside

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Does anyone know anything about these 387SX SBC's, I own two of them that I bought off eBay for $10 a piece a few years ago , I really bought them to take the 4mb 30pin SIMMs , but I was recently digging through the crap in my closet and rediscovered them and I am looking into possibly making builds with them, do they work in a standard PCIMIG backplane or do they require something special?

They seem like they could make a fairly nice and fast little 387sx box since they have a 40mhz 387sx and it looks like it should support a full 16mbs of ram , they appear to have been manufactured towards the end of 95 or early 96, there are date codes ranging from the 26th week of 95 to the 48th week of 95 on the ICs. They have a 387 co-processor socket, although I don't know what software can run well on a 386sx that would benefit from it. AN IDE channel is provided, a floppy controller is provided, there are 2 serial ports on the back of the card, It has a PS/2 keyboard connector along side the serial ports, there is a header on the board for a parallel connector, so I wouldn't need an I/O card. I would have to dig out my ISA video card video card, and I would need to pull a sound card out of one of my ISA systems to get sound, although it looks like a header is provided to connect a system speaker so I could at least get some basic sound from that.

EDIT: Changed title because most of the thread is now about the TMI 2001A CHASIS

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Last edited by i486_inside on 2017-07-13, 03:11. Edited 1 time in total.

Reply 1 of 15, by i486_inside

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I rigged up an old ISA riser card, with pin 1 connected to gnd, pin 3 connected to +5V , and pin 9 connected to +12V on a molex connector on another machine, and I plugged a keyboard into it, the lights on the keyboard flash on, then it sounds like short beeps, which means first 64k memory failure in AMI beep codes. My rig was pretty shotty , so I think I might just cave and buy a proper backplane for $30-40 off ebay to do some further testing/trouble shooting.

Reply 2 of 15, by i486_inside

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Well, I caved, and bought this, http://www.ebay.com/itm/TEXAS-MICROSYSTEMS-MO … =p2047675.l2557 , for 56 bucks shipped, the seller said it has components in the case, so it should at very least contain a 10 slot ISA backplane and a 150W PSU, but My guess is it probably has a whole 486 SBC in it along with everything else needed to run it. At least now I will have a platform to test SBC's on.

Reply 4 of 15, by i486_inside

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I got my Texas Micro 2001A today.
When I recieved it was configured with:
Texas Micro 12Mhz 286 SBC
256k Trident 9000 VGA card
Western Digital IDE and Floppy Card
Conner CP3024 Harddrive
5 1/4 Floppy Drive
Serial/Industrial Machinery Control Card
Serial/Industrial Machinery Control Card

When I fired it up with all of this it gave a bios post error, but I don't know what it was, I have trouble understanding Pheonix's beep codes.

So I took out the Texas Micro SBC and put in one of the JJ-Tech boards and it posted but it would not hold CMOS settings. which means I will have to replace the Dallas Chip if I want to use it.
I ended up removing the WDC IDE Floppy card because the JJ-Tech has onboard IDE and floppy and I tried the JJ-103 and it gave memory failure post code so I swapped the memory from the other card and it booted and still had old configurations saved in the CMOS.

I don't have any 5 1/4 floppies, and the computer only has full sized molex and I don't have any many molex adapters so I stole the 512mb DOM out of my Compuadd 316s that had Windows 95 installed on it , along with the 512k et4000 and a sound card that I had previously borrowed from my packard bell.
The Tseng ET4000 did not want to install properly and kept hanging during detection so I though there might be a resource conflict and I removed the two random industrial cards and was finally able to get the GPU installed. Windows 95 is almost actually usable on the SX40 with 16mb of ram vs the SX16 Compuadd with 4mb of ram. The few light games I tested from the Microsoft Arcade Pack and DX-Ball seemed to run smoother with sound enabled than the SX16 which would absolutely choke when sound was played, DX-Ball slows down during intense action like explosions but still kind of impressive that it even works at all on a 386.

Here are some pictures of cards I pulled from the 2001A.

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Reply 5 of 15, by xjas

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Neat! Glad to see you're getting somewhere with these. I love these SBCs and I love the idea of a modular computer where you can just pull out the system board & swap it at will - that said, haven't bothered to do that with any of my own yet. Once built they tend to stay built. 😜

What make CPU is on the 286 board?

The Dallas RTC battery hack isn't that hard to do, I've done it. It just takes some patience and a steady hand.

twitch.tv/oldskooljay - playing the obscure, forgotten & weird - most Tuesdays & Thursdays @ 6:30 PM PDT. Bonus streams elsewhen!

Reply 6 of 15, by i486_inside

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The CPU on the 286 board is Intel N80286-12

I don't know If I'll even bother replacing the clock chip on the JJ-Tech card with a dead battery since I don't really have any way to use two of these, I guess I'll repair both cards when the working clock chip finally dies.

Last edited by i486_inside on 2017-07-07, 06:53. Edited 1 time in total.

Reply 7 of 15, by i486_inside

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I would expect that there is not much life left in the clock chip on the working card since both cards seem to be from the same batch and use a clock chip with a 36th week of 1995 date code.

Reply 8 of 15, by i486_inside

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DX-BALL running on 386SX-33
https://www.youtube.com/watch?v=5Npr5fWHd-E

EDIT: CPU is only 33 Mhz not 40 Mhz

Last edited by i486_inside on 2017-07-08, 09:35. Edited 1 time in total.

Reply 9 of 15, by i486_inside

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I got my networking adapter today( realtek 8019)
I also got my 1MB cirrus GD5422 today.
I took the ET4000AX out and rightfully returned it to the CompuAdd 316s, the card is a DFI VG-5200.
I didn't have any of the files for networking on the Windows 95 install so I had to take apart the 2001A which Involves removing 10 screws and then I had to remove the 3.5in bay which is held in by 4 fine thread screws the I had to remove the 5.25 bay that is held in place by yet another 4 fine thread screws. I also removed the fan from the Back of the case, since it was dead and the blades were crumbling , It is a 120mm? Comair Rotron AC fan, the AC leads were spliced into some other wires so I just cut them off and taped over the ends with electrical tape I plan on replacing the fan with a 120mm DC fan. For now I have Installed an Antec Slot blower in the case to provide some air flow, the front part of the case where the PSU is at seems to stay cooler now.

I have ordered a 387 because I found some electronic supply house on eBay that was selling NOS IIT XC87SLC-33's in pairs fro $13 shipped.
From my understanding the IIT Co-pro always run synchronous with the CPU which shouldn't be a problem because it appears that the CPU only runs at 33mhz, at least that is what Speedsys reports, but it is probably accurate since upon further inspect the boards have a 66mhz oscillator. 33Mhz is probably fast enough anyways the card seems to run plenty warm at 33mhz.

Here is a picture of the Trident card that came in the 2001A, and a picture of the 2001A with the CD-ROM installed with a measuring tape to show that the unit is 4U tall. I though I snapped a picture of the ET4000 but it was not in the pictures on my phone.

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Reply 10 of 15, by i486_inside

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I got my fan today in the mail, it is a 1700rpm 120x38mm NMB fan, I set it up as an exhaust fan even though the original fan was setup as an intake, they originally set it up that way because the fan had a dust filter on it and they were trying to control how much dust got into the case, but since I can easily clean the dust I think it is more beneficial for me to use the rear fan for exhaust and have air sucked in through the holes along the side of the case. I also connected up the HDD LED which I original thought was too short but today I realized that it was folded over several times and zip tied, so I has to cut off the zip tie and in the process I think I knicked the wires a little bit, I really hate zip ties, and actually I don't know why they used them iside an industrial computer since they are meant to be quickly serviced and zip ties are always a bitch to remove from wires. I also took several pictures of the TMI 2001. Notice there are two separate areas of the case, one side houses the back plane , and the other side houses the high voltage components and the drive bays. The High Voltage side is a pain to open because there are like 15 screw that hold the panel in place, there are only 3 screws that hold the cover over the side with the backplane.

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Reply 11 of 15, by i486_inside

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I decided that I will replace the dallas chips, I was looking into the alt12887 project but seeing how it cost about $12 for all the parts and takes a few weeks to get it and I would still have to do some assembly I decided I will just buy some newer DS12887 chips off ebay and install a DIP socket on the card since DS12887 can be had for less than $10 a piece from within the US and you can get them for about $2 a piece in quantity from china .

Reply 13 of 15, by i486_inside

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I bought some 80mhz oscillators, so when I do the solder work for the clock chip I will also desolder the oscillator socket that is up by the co processor socket that I don't need since I can't run the IIT Co processor asynchronously and desolder the main oscillator and put in the socket so that I can swap out oscillators?
If I can get it to run stable with the 80mhz oscillator that should put the CPU at 40mhz which should run stably since the CPU is actually a 40mhz part conservatively clocked at 33mhz and I would think the IIT coprocessor should run stably at 40mhz because my chips were manufactured in 1993 which was pretty late in the 386sx lifespan so the manufacturing process would have been quite mature and the 33mhz variant was the highest factory clocked sx/slc co-processor they offered which means that they would have been the highest binned chips too so it wouldn't surprise me if the 33mhz version could easily be clocked to 40mhz and run stably. Also I would think that changing the oscillator would change the ISA clock which I assume runs 8:1 with the main oscilator which means with the 80mhz oscillator in place it would run at 10mhz which could either destabilize everything or give a nice performance boost to the bandwidth starved ISA video card. Increasing the clock should increase the memory bandwidth some which any extra bandwidth is welcome give the bottleneck of the 16bit data bus and the lack of cache. I am almost half tempted to get a hold of a 486slc and do a little solder work, I would think the card would be able to support it since the bios has an option to enable internal cache, although I'm not really sure I want to tackle soldering the little qfp though.

What experiences have you had trying to run the ISA bus at 10mhz.

Does anyone have any recommendations for software that can practically take advantage of the co processor?

Reply 14 of 15, by i486_inside

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I got the solder wick from amazon today and went to desolder the existing clock chip, long story short my Chinese eBay station spent a little time airborn, and I bought a Hakko station bundled with several tips off of amazon.

See my tutorial video on how to properly use a Chinese no name solder station : https://www.youtube.com/watch?v=9jjMxFl0c1M&feature=youtu.be

Reply 15 of 15, by i486_inside

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I ended up buying a vacuum desolder station because I couldn't wick all the solder out the the thru-holes to get the ds12887 out.
I got the chip out, and got the new socket soldered. The Dallas chips I ordered off ebay were surprisingly new, they had a 31st week of 2016 date code.
I also replaced the oscilator with the 80mhz one, it seems to have made everything faster, although my speedsys cpu score went down from 5.56 to 5.34, but everything else was faster, Doom demo 3 on minimum went from nearly 5000 realtics ~14fps to around 4000 realtics (~17fps) , speedsys shows the gpu went from ~3300kbs to ~4000kbs, the disk drive results were a lot faster. Topbench score went from around 61 to 75. 3d bench went from 10 to 12.