The shortest run I ever had with a 286 (EVEREX 1800) \ VOGONS

The shortest run I ever had with a 286 (EVEREX 1800)

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First post, by Jed118

Posted on 2020-04-21, 02:55

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So I bought this 286 from Kijiji locally for a fair price for an incomplete system (no HDD/FDD) in a good case with a 286/10 that had 1Mb of RAM and POSTed. My plan was to fill its bays with stuff to make it a working computer.
The board is similar to this one here:

https://stason.org/TULARC/pc/motherboards/E/E … 10-EV-1801.html

Here it is, cleaned up:

I was filming the disassembly and then I ran out of room on my camera, switched to an SD card, and the Gods of 30+ year old tech refurbishment flashed me with an omen - last 2 hours of footage corrupted. I was making good progress - I removed the incredibly dusty board, took a new, clean paint brush to it to brush all the dirt off (I'm afraid of vacuum cleaners in computers, as I think that's how I fried the VRAM on an integrated video Pentium system a while ago) and put it all back together. Happy with my progress, I resolved to re-shoot tomorrow.

(*edit - there was no filming done today, just plugging away at the 286 over lunches and breaks) Today I was slowly loading software onto it, no issues, it was on for most of the day, immobile on my desk. Upon a planned reboot, terrible sounds came out of the PC speaker, as if someone was pressing all the keys: There were several tones at one point, then "Keyboard error". The keyboard I was using admittedly wasn't the best and gave me similar problems (key stuck, I fixed it a while back) but not with this degree of "panic" sounds from the PC speaker. I pulled out the keyboard and plugged in another one (a Win 95, but DIN) and kept on going. A couple more reboots, the situation gets worse.

I swap the keyboard BIOS. Computer resumes cooperation. I start looking around the PC, saw nothing obvious. I'm looking at all the discrete components, thinking shit, did I ESD one with the paint brush?

That was the last time it booted properly. Next bootup, I get Keyboard/Interface Error. Now I know I'm f**ked. Indeed no amount of chip swapping or blowing did anything, except for two times where I was able to press ESC and the RAM count skipped (right after swapping in a MR BIOS 1993 DIP), and another time I was able to skip the RAM count again after moving the CRT COL/MONO switch (right beside the keyboard BIOS) . Oh and once in a while on a random BIOS it will stop at 128k RAM count, sit for a while, then lurch forward, sometimes making it 1024k. This almost always happens when the keyboard is in XT mode, or I have an XT keyboard plugged in. Horrid sounds are minimized, now they sound like a short gurgling after the RAM count.

In all cases
-Keyboard BIOSes work in other machines (all of them I put into this 286)
-Keyboards themselves work with other machines
-3 LED flash occurs on keyboards
-Removing the Keyboard BIOS shows NO KEYBOARD BIOS FOUND (or something like that) SYSTEM HALTED
-BIOS Code reader stops at 84/85

I've taken the board out completely and pushed in all the RAM chips and whatever else is socketed, did the drop test (and in so doing reset all the DIP switches - enough footage survived to undo this), shaken the dust off it, looked around for obvious failures, and ran the board with minimal I/O. Still at Keyboard/Interface Error.

These boards are a bit before my time, but does anyone have a clue, hell I'll take speculation, as to why the keyboard interface stopped working?

Last edited by Jed118 on 2020-04-21, 03:45. Edited 1 time in total.

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Reply 1 of 7, by Horun

Posted on 2020-04-21, 03:04

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Jed118 wrote on 2020-04-21, 02:55:

I was filming the disassembly and then I ran out of room on my camera

That was the last time it booted properly.

Uhh.. Guess it better to pay attention to what the board is doing than the camera ? No offense but I do enjoy the vids some here make but at the cost of a board because you were more intent on filming than getting it running just sends shudders down my spine. Have no clue what is up. Good Luck !

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 2 of 7, by Jed118

Posted on 2020-04-21, 03:28

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Horun wrote on 2020-04-21, 03:04:

Uhh.. Guess it better to pay attention to what the board is doing than the camera ? No offense but I do enjoy the vids some here make but at the cost of a board because you were more intent on filming than getting it running just sends shudders down my spine. Have no clue what is up. Good Luck !

🤣 WAT? I press "record", the thing's on a tripod pointing down at the table, I know the card's full because I get an audible beep.... This isn't the 1920s where I have to hand crank a 200 kilo camera on rails.

The board slowly failed throughout the next day, no camera was present. I may not have the most component-level experience with this stuff, esp. stuff this old that is before my time, but come on man, the board failed because I was filming it? ROFL!

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Reply 3 of 7, by Anonymous Coward

Posted on 2020-04-21, 08:51

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Although it's not likely, check the keyboard fuse. It's normally located near the keyboard port and often labelled "F1".

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V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 4 of 7, by quicknick

Posted on 2020-04-21, 11:02

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The part where it sometimes "listens" to the Esc key and skips the memory test rings a bell for me, see this thread.

The problem could be similar on your board, and I think it's easier to diagnose since it uses discrete chips for everything. I'm attaching the three BIOSes that helped me to somewhat narrow down the search for the problem in my case, and also I can recommend using the Supersoft diagnostic ROMs.

Good luck, and best wishes to you and your board 😀

Reply 5 of 7, by rmay635703

Posted on 2020-04-21, 20:15

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One of my systems did that and there was current leakage between the keyboard pins, in my case the board looked like it got too hot locally to the keyboard mount

Never did fix, still sitting in my pile.

Reply 6 of 7, by Jed118

Posted on 2020-04-21, 21:15

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quicknick wrote on 2020-04-21, 11:02:

The part where it sometimes "listens" to the Esc key and skips the memory test rings a bell for me, see this thread.

The problem could be similar on your board, and I think it's easier to diagnose since it uses discrete chips for everything. I'm attaching the three BIOSes that helped me to somewhat narrow down the search for the problem in my case, and also I can recommend using the Supersoft diagnostic ROMs.

Good luck, and best wishes to you and your board 😀

I have many questions. I also have some exams to do 🙁

I found a tiny iron filing on the backside of the board, looked like it was jumping some connections between the keyboard connector lines. I removed it and powered up the board, but yeah, not that easy. I'm worried there might be more and I don't have a compressor or air-in-a-can.

It's the tiny curved piece just above the red lightning bolt icon. It does conduct electricity.

I looked at the board for fuses, I think I found four of them, as none of them provide any resistance and flow both ways.

I powered the board up and measured them, and the four of their voltages corresponded to their connections on the keyboard port. I've determined PIN 4 is GND. Pin 1 fluctuates, starting at -30 mV, to +120 mV, and from there it slowly climbs to 190 mV, stabilizes for a bit, then fluctuates all over. I bet if I had a scope the readings would make more sense. Also if I knew what the nominal values were.

Can anyone point me to schematics for this kind of stuff? I know where to get them individually, but I would like to know how they interact with each other on this (or any, really) board.

My gut tells me something is happening at PIN 1.

*edit - ext battery says specifically 3.6. I just refilled the batteries that came with the computer, three double A cells, giving 4.5. I've seen some Compaq LTE BIOS cells as high as 7.2v, but is adding 0.9v here going to be a problem?

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Reply 7 of 7, by pentiumspeed

Posted on 2020-04-21, 23:34

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Yellow cylinder, axial component on left of this keyboard connector is your only fuse for the keyboard.

Rest of others is capacitors, some tantulams and glass body capacitors, resistors. Nearly all inductors (dark grey body) reads zero resistance.

Cheers,

Great Northern aka Canada.

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