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First post, by kawe-dus

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Hello,
today i recieved a new "black box" Desktop System which i bouhgt on ebay Kleinanzeigen in germany with a little hope that it will be a 286 System.
But today it seems to be my lucky day bacause when i switched the system i recorgnized that it is an old XT System with an Siemens 8088 Processor.

At the post screen it counts the RAM up to 640K and shows me a message from the build in Seagate MFM Controller that the Kaolak MFM Drive iss configured. But here the system stops with an error and want the F1 Key to move on.
Unfortunally the system don't recorgnized any of my old DIN Keyboards. i cannot press the F1 Key, nor the numlock, capsloc LED can be switched on.

When i power on the system the three lights of the keyboard are glimming for aprox. a half secound (as they are at normal AT Systems when they switched on)

The Mainboard seems to running an XT BIOS from AWARD.
When i take a closer look it seems that there is an IC with the Label "ASIC" missing.

The Mainboard is equiped with an Keylock Option wich, said the manual, must be shorted when the keylock should be dissbled. I allready tryed to short the Keylock with an jumper, but this changes nothing.

Is this IC maybee the reason why the keyboard is not usable ?
What for other reasons can prevent the system from recorgnizing the keybord.

unfortunally i find no further infos to the mainboard the manual said the modell of the mainboard is BS-111

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Reply 1 of 14, by Deksor

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XT computers use a different keyboard protocol. You can't use an AT-PS/2 keyboard on an XT without an adapter.
Some old AT keyboards have a switch somewhere to switch between AT and XT, but they're not very common

By the way this manual and motherboard would be welcome on Theretroweb.com 😁

Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative

Reply 2 of 14, by kawe-dus

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Deksor wrote on 2023-05-18, 19:39:

XT computers use a different keyboard protocol. You can't use an AT-PS/2 keyboard on an XT without an adapter.
Some old AT keyboards have a switch somewhere to switch between AT and XT, but they're not very common

By the way this manual and motherboard would be welcome on Theretroweb.com 😁

shit, i remember, far far away, i owned an keyboard with an XT/AT Switch. But the keyboard is long gone 🙁 - I tryed to use an real AT Keyboard, not an PS/2 Keyboard, only for clarification 😀

do you know where i can find an suitable adapter or an old keyboard modell which i can search at the common auction platforms ? because the manual is only a few pages long i can scan them in the next days and put them on theretroweb.com 😉

Reply 3 of 14, by Deksor

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Sadly I don't know if there are XT keyboards that are clearly recognizable, other than a few like the IBM model F keyboard, but that one costs a fortune nowadays.

Adapters must be active as you need to do some signal conversion.
I found this https://www.ebay.com/itm/283738884563 but there are many others and you can probably DIY one yourself.

I mentioned PS/2 keyboard because AT and PS/2 keyboards do use the same signals and can be swapped independently (as long as you adapt the plug of course)

Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative

Reply 4 of 14, by kawe-dus

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Deksor wrote on 2023-05-18, 20:14:
Sadly I don't know if there are XT keyboards that are clearly recognizable, other than a few like the IBM model F keyboard, but […]
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Sadly I don't know if there are XT keyboards that are clearly recognizable, other than a few like the IBM model F keyboard, but that one costs a fortune nowadays.

Adapters must be active as you need to do some signal conversion.
I found this https://www.ebay.com/itm/283738884563 but there are many others and you can probably DIY one yourself.

I mentioned PS/2 keyboard because AT and PS/2 keyboards do use the same signals and can be swapped independently (as long as you adapt the plug of course)

thank you for the link. i will look for a suitable converter closer to my area to save the shipping/custom costs.

the missing of the ASIC / BASIC Chip still concernes me. does the system need such an IC to work proppertly or is it an optional thing ?

Reply 5 of 14, by rasz_pl

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if you have any tinkering inclinations you can do it with $5 arduino clone board. Afaik teh only difference between AT and XT is scancodes and maybe message format?
http://www.ccgcpu.com/2019/02/14/the-xt-part- … rnish-keyboard/
https://oshwlab.com/sundbyk/xt-keyboard-converter
https://github.com/kesrut/pcxtkbd https://www.youtube.com/watch?v=HJOUtIbPJsg
http://asknotes.com/2021/09/19/ibm-5150-xt-keyboard-adapter/
https://github.com/luporl/at2xtkbd
https://github.com/jedimatt42/teensyUSBtoXT

Reply 6 of 14, by kawe-dus

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i can't belive it, but i found an cherry g81 Keyboard with an AT/PC Switch in my basement. Now i am able to boot the system from the MFM Drive.
unfortunally i'am not able to use the buildIn 5 1/4" and 3,5" drive. the LED on the Devices are going on when i access the drives, but they cant read or write any data.

both drives have no modell or partnumbers printed on the drives so i am not shute if they are 360/1,2 Mb or 720K/1,44 mb drives.

to check the specifications i tryed to enter the setup. but no key combintions seems to be working.
now i am a little bit lost.
luckily IBM DOS 3.2 is installed on the HDD so i can start an operating system.

anyone have a clue how i can enter the setup on an award XT BIOS Vers. 2.05 ?

Reply 7 of 14, by Deksor

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There's no such thing as a setup on an XT 😀. This came with the AT systems (and early AT didn't have in bios setup either, you had to use a floppy disk). This is configured via jumpers on the motherboard. But unless somebody messed with the motherboard I think they should be configured properly.
Can you try these drives in another system ?

Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative

Reply 8 of 14, by Rwolf

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What I recall, the missing BASIC ROM should not be a problem; IBM had a BASIC interpreter that was partly residing in ROM and partly in an executable on disk, and if you had an application in BASIC it used both (I guess it was split to prevent copying of just the executable to a clone PC).

However alternate BASIC interpreters, like GWBASIC were developed that did not use the split functionality, and those were often installed on clone PC:s instead of the IBM version that also needed the ROM.

Reply 9 of 14, by kawe-dus

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Deksor wrote on 2023-05-19, 21:26:

There's no such thing as a setup on an XT 😀. This came with the AT systems (and early AT didn't have in bios setup either, you had to use a floppy disk). This is configured via jumpers on the motherboard. But unless somebody messed with the motherboard I think they should be configured properly.
Can you try these drives in another system ?

I think that will be my next task. I own a few 286 and 386 systems which should test both flopy drives.
I giving an update when i finished the tests.

Is it possible to connect 1,2 and 1,4 mb drives to the system and running them in the 360k and 720k mode ?

Reply 10 of 14, by Deksor

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1.4MB drive should be fine with 720K mode, however 1.2MB drive is a little bit more *complicated* ...
Basically the spinning speed of 360K drive and 1.2MB drive is different and the size of the read/write head is also different. This means that reading *should* be fine (at least for standard DOS stuff), but writing may lead to write errors and also the disk will probably not be readable on another 360K disk drive.

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Reply 11 of 14, by konc

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kawe-dus wrote on 2023-05-19, 19:39:

both drives have no modell or partnumbers printed on the drives so i am not shute if they are 360/1,2 Mb or 720K/1,44 mb drives.

If they look original, they are DD (360 & 720K). Heck even if they don't it's unlikely that they are HD, especially the 5 1/4

Reply 13 of 14, by weedeewee

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Kekkula wrote on 2023-05-21, 07:41:

And as I resently learnt, not all newer 1.44 drives support reading 720K disks 🙁

if you're talking about usb floppy drives, that would just be a firmware limitation of the usb floppy interface.

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Reply 14 of 14, by Kekkula

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Actually I wrote the disks with IBM USB floppy drive and tried to read them with Sony 1.44mb drive, witch reads 1.44mb floppies just fine, but didn't read 720K disks... At least in my xt machine, after swapping to older 1.44mb drive I was able to read the 720K disks just fine.