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386DX-16 Industrial Single Board Computer - Keyboard Issues, etc.

IBM

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I recently acquired a 386DX-16 Industrial SBC by Texas Microsystems Incorporated (TMI). It is a typical full length ISA card that plugs into a passive backplane.

I am unable to find documentation or jumper settings for it, but that aside I can't get a keyboard to work with it.

In an AT-type passive backplane system, the keyboard connector is on the backplane itself, and I assume the controller is on the actual SBC. The system boots up perfectly but it always gives a "Keyboard failure" error. I have tried other keyboards and other passive backplanes but I can't get any keyboards to work. The capslock-numlock-scroll lock lights briefly flash when the system is powered up but that is all they do. I cannot toggle them nor does the keyboard work in any way. There is also a strange 8 pin power connector on the sbc with an unusual "double molex" ended cable, which I have no idea what is for.

Can anyone tell me anything about any of this?


Here is an identical card that sold on eBay:
http://www.ebay.com/itm/ws/eBayISAP...sspagename=STRK:MEWNX:IT&orig_cvip=true&rt=nc


Thank you,
Isaac
 

Chuck(G)

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Looking at other Texas Micro SBCs, there should be a single-row 8-pin header for the keyboard near the bottom of the card.
Code:
CPU Keyboard Interface Harness             






                         _ SPEAKER
                        | \
                        |  \+ __BLK______
                        |   ____GRN_____ \
                        |  /            \ \                            DIN
                        |_/              \ \                           CONNECTOR
                                          \ \
Speaker  1 GRN-----------------------------\ \------------------------BLK 5
+5V Out  2 BLK--------------------------------------------------------BLK 5
Kb Lock  3 -----                                                              
Kb Data  4 WHT--------------------------------------------------------WHT 2   
Kb Clock 5 BRN--------------------------------------------------------BRN 1   
Kb Reset 6 ORN--------------------------------------------------------ORN 3
Ground   7 RED--------------------------------------------------------RED 4
Reset    8 BLU------------------| |-----------------------------------RED 4
                                | |                                     
KEYBOARD                        | |                                     INDUSTRY
HARNESS                         | |                                     STANDARD
PLUG                            | ------------RED--|_                   KB PLUG
                                |-------------BLU--|
                                                    OPTIONAL
                                                    RESET 
                                                    SWITCH

Oh yeah--the switches on SW1 1-4 should be "off".
 

patscc

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Chuck(G) said
Looking at other Texas Micro SBCs, there should be a single-row 8-pin header for the keyboard near the bottom of the card.
Yeah, that's the problem I'm having, too. The ebay picture doesn't have any headers on the bottom, just a header that looks like a AUX power connector. To the right of the SIMM are what look like two 40-pin headers.
I wonder what the heck the 1/8" jack on the back of it is for.
patscc
 

Chuck(G)

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Yeah, that's the problem I'm having, too. The ebay picture doesn't have any headers on the bottom, just a header that looks like a AUX power connector. To the right of the SIMM are what look like two 40-pin headers.
I wonder what the heck the 1/8" jack on the back of it is for.

I'll wager that that connector has 8 positions and that there's continuity between pin 2 and the +5 rail and pin 7 and ground. TexMicro had their own passive backplanes with a connector for that header.

The 1/8 jack--I dunno. Possibly external battery (I'll bet that the "Keeper" battery is dead) or external speaker?
 

IBM

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Ok several things. There is no five pin header anywhere on the thing. The jack is for the PC speaker. Believe it or not, the Keeper II is not dead! The other white little switch next to it is a reset button. BIOS is dated 1988. OF the four DIP switches, 2 and 3 are set to off and the others are on. It booted fine but couldn't detect the keyboard (or a drive).

I did look on Statson and found that card, but that's not it - it is totally different.

Oddly, the eight pin header has a cable that terminates into what I can only describe as a dual 4-pin molex with locking latches. I figured it was power relatated.

So how the heck can I get keyboard support? Or where I can get a 386/486 ISA SBC without paying a fortune if I can't get this to work? Wish I could find documentation but there's no identification on the card other than "Made in U.S.A. 572-A-0301."
 

patscc

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Say, could we get some pics of the underside of the board ? There's always a chance one of the 40-pin headers is actually for a port harness. I've seen some kiosk machines set up like that.
patscc
 

IBM

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I'll post some pictures later today. I think the 8 pin connector may indeed be for the keyboard - if so, I can work with that.

You say the DIP switches should all be off - what do they do? Also, what are the 40 pin headers for? There are a few jumpers as well, one of them on a 40 pin header. Is there a watchdog timer on this SBC? What makes this board, or any board for that matter "industrial?" What do you suppose it was used for?

Also, the Keeper, though it works, will eventually fail and I doubt I can get a replacement. Or is there? I have seen Dallas RTC chips modified to have an external battery. Could this be done to a Keeper as well?

Where are you getting all this information anyhow? I couldn't find anything on this board. Sorry for all the questions but I don't know anyone else who would potentially know all this.

I thank you in advance.

-Isaac
 

Chuck(G)

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The DIP switches are, according to one source, for factory diagnostics.

Most of the information is courtesy of archive.org and a lot of google-fu. There was also a Tex Micro 486 series. TM was swallowed up by Radisys. I don't think they'd know anything about the old Tex Micro stuff, though.

I think that the Keeper is nothing more than a Dallas clone.

From memory, these were used in a couple of defense applications; I remember a Navy system mention and I think a NASA mention.

What makes these passive backplane systems useful is that if something fails, it's easy to replace. No taking the whole thing apart with lots of cables, screws, etc. Just pop a replacement in and you're good to go. Very popular in industrial process control, where downtime can cost big. There are PCI versions of these things also.
 

IBM

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Ok, I managed to take those pictures. The cord is only a foot long or so.



Let me know what you think.

Thanks,
Isaac
 

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patscc

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On the component side of the board, under the label, I'm wondering if that might be a keyboard controller. Can you make out any part numbers on it ?
patscc
 

patscc

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Okay, maybe definitely is a bit strong.
This is why I was curious to see if the upper-right hand, taped over chip might not be a keyboard controller, because then we can see if pins 4 & 5 go there.
At first glance I thought pin 4 wasn't connected on the connector, but on second look, I think I can see a white wire lurking in one of the pictures.
I'm a bit rusty, so sorry about that.
patscc
 

IBM

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I tested the pins with a multimeter. On the eight pin connector I am assuming that pin 1 is actually the rightmost one based on the orientation of my pictures.

If this assumption is correct then:

Pin 2 is +5V
Pin 7 is ground
Pin 4 connects to pin 22 on the right uppermost IC
Pin 5 connects to pin 1 on the right uppermost IC
That upper-rightmost IC is covered by the label but part of it reads ...08742 7490141 Intel '82
 
Last edited:

patscc

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You might want to try re-seating the IC. Probably won't do anything, but simple enough to try.
Out of curiosity, is there a bump underneath the paper (I'm wondering if there's a window there) If no bump( window ), could you peel back the label a bit more to see if there's a recognizable part number ?
I'm assuming you don't have a scope ?
patscc
 
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