Re: 80286 Mainboard Bios needed

Posted on 2019-05-07, 20:09

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Seems it has 8 Samsung KM44C256 installed. Those are 256k x 4 bit DRAMs. So yeah, I think it should have 1 MiB of RAM. But don't BIOS's usually automatically detect the amount of RAM? https://pdf1.alldatasheet.com/datasheet-pdf/view/125858/SAMSUNG/KM44C256A-8/+02W87-VPvLyUPI+OyCwlwGHMML+/datasheet. …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-07, 17:23

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hi Deunan, happy that you also like these boards and bought one ;-) You should have told me, I have at least one in spare that is not running smoothly and would have been happy to give it to you. Who if not you would be able to repair it? :cool: :cool: :cool: As far as I know all of these boards I …

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Re: 80286 Mainboard Bios needed

Posted on 2019-05-07, 17:12

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thats good news! Too lazy to google the ICs...but for me there seems to be only 512K on the photo installed?

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Re: Suntac 80286 Mainboards

Posted on 2019-05-07, 15:02

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

As in the latest board the keyboard BIOS was damaged by corrosion (top on picture) I tested some other replacements I had in spare. I think they are from 286-486 class PCs. Also took one from anoher 386 board, not on picture. All work without problem. They seem to be interchangable between CPU …

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Re: IBM XT 5160 motherboard not POSTing

Posted on 2019-05-05, 20:29

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

By the way, there is some life in that board : when I put my POST card in it, I see the numbers moving really fast (I think it's an incrementing value. It's really going too fast to read anything, but I think I see the pattern of a hex number being incremented), then it stops on "0F" shortly, then …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-05, 20:22

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

yes, please upload everything you have 😉

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Re: Suntac 80286 Mainboards

Posted on 2019-05-05, 19:47

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thanks for uploading, works! Is there any way to get into the Setup..? Didnt find the correct key? Or only provided on floppy? Filename IMG_4638r.jpg File size 1.66 MiB Views 1334 views

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Re: Mouse systems Optical Model M-4 Drivers

Posted on 2019-05-05, 10:28

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Dont know if its similar here. For my Genius 3-button mouse I had to keep the left (or left+right?) button pressed while switching on the PC to switch the mouse MS-compatible. Maybe worth a try...

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Re: 80286 Mainboard Bios needed

Posted on 2019-05-05, 10:17

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I would start with https://www.vogons.org/viewtopic.php?f=46&t=17341&p=752362&hilit=tact#p752362 Or there is also a TACT8230 at chukaev. Maybe they are compatible... *TI (Texas Instruments) **SN74LS610/2 IBM AT: SN74LS610, SN74LS612 Memory Mappers <84... **TACT82000 3-Chip 286 [no datasheet] c89... …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-05, 09:45

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, crystal seems to be 24 MHz so CPU seems to be running at 12MHz. But its labeled as 8/10/12/16 so it might be possible to oberclock? Never tried... For RAM upgrade I woiuld recommend a EMS/XMS card like this one ;-) https://www.vogons.org/viewtopic.php?f=46&t=66089&p=747843 At least you can use …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-05, 08:41

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Also, I don't know what the JP2 jumper on the test card is for. The card came with some wire to connect this JP2 jumper somewhere. There's also a button on the test card which I don't know the use of. The user manual is in english but probably badly translated from Chinese like many products of …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-03, 16:45

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

OK made a better soldering work on the 74LS14: This cabling works perfectly on every reboot! Summarized: - board appears to be totally dead with broken delay line - 74LS14 is a good replacement but need to consider the required connectors on a case by case basis - Deunan is the best, many thanks for …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-01, 19:08

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

OK, almost there with wiring 1 - in 2 -> 13 12 -> 11 10 -> 3 Maybe it was just by chance as its not very reproducable. Did this with loose wires and will solder on the weekend. But there seems to be another issue. Keyboard does not work and NumLock LED is very dark. At least one jumper needs to be …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-01, 16:43

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, original is the ESAN 31A-5101. It has 100 ns total and 20 ns per TAP. Pinout is on the bottom right of the datasheet at the top the other thread: https://www.vogons.org/viewtopic.php?f=46&t=66568&p=751131 Connected on the mainboard seem to be Pins 1, 4, 8, 12, 14 dl.jpg (bottom view mirrored) …

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Re: Suntac 80286 Mainboards

Posted on 2019-05-01, 13:37

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Hmm, did a better wiring job with the HCT but unfortunately still the same result...think I need to test with a known working delay line to be sure its the reason for the fault...

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Re: Bought these (retro) hardware today

Posted on 2019-04-30, 21:16

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by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Scored this motherboard today! It's a Yang An YA-1. It has Vesa AND EISA! I have never seen an EISA motherboard before, and am excited to get this working. Unfourtunately, it has some quite serious corrosion due to the battery leaking on the board. It obliterated most of the traces in the vicinity, …

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Re: Bought these (retro) hardware today

Posted on 2019-04-26, 21:16

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Won this auction for 5.50 € incl. shipment (sellers photo) s-l1600 (1).jpg Not really interested in these modern PS/2 RAMs, but I spotted some 30 Pins inside which are rather hard to get for a good price. And indeed, I received about 10 of them along with these 2: DSC_8500.JPG These are 16MBs :cool: …

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Re: Suntac 80286 Mainboards

Posted on 2019-04-26, 20:02

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes, I am afraid thats a good explanation. I dont like to desolder a working delay line to verify. Therefore I will try with 74HCT14...

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Re: Delay line modern replacement?

Posted on 2019-04-26, 18:04

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by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Dont have a soldering iron here, therefore I made a quick&dirty fix 😈 Filename DSC_8498.JPG File size 948.86 KiB Views 616 views Result here...: Suntac 80286 Mainboards Thanks again!

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Re: Suntac 80286 Mainboards

Posted on 2019-04-26, 18:01

by

by Predator99

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

2019-1-26 @ 11:35 Did not manage to fix it so far... But next one: 286-Suntac-A2125580.jpg After some cleaning it looks better: 286-Suntac-A2125580--cl.jpg Seems to be alive, but the delay line in the bottom left is loose, almost all pins broken. Need a replacement... BIOS: 286-Suntac-A2125580.rar …

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