There is a 30MHZ QCO and the 8088-1 CPU indeed runs at 10MHz (verified by oscilloscope). I do not recognize a bus controller-IC (like for example a 8288). I assume that this is done by the mysterious M78H1012A in the QFP 100 package:

I really want a datasheet for this IC, but I haven't found anything yet.

The board has VIP written on it and there is a logo that I cannot identify. I assume AUVA? It has two 8-position DIP switches. The one closer to the CPU has probaply the same funtionality as on an AUVA TXM 8/ 10. (not fully tested yet). No clue about the other one.

The original BIOS IC was "unreliable" and but I think was just a contact problem I could read it with my EPROm programmer after carefull cleaning all the pins. I burned a new 27C64 just to be sure. This is what the BIOS startup screen looks like:

Now.... I could not find this board in any "retro"-mobo-collection that I know. I would like to know the manufacturer and model. Any documentation, a manual or a DIP-switch/jumper manual would be awesome.
Does anybody recognize the logo? A datasheet for the M78H1012A would be awesome too.

If I can find the time I will try to boot from a 720K Gotek Image.

Thank you for reading 😀

In the early 90s, we had an XT with a 360 KB 5.25 floppy disk in the office, then the 3.5" 1.44MB reader was added, and the controller was replaced, unfortunately the 1.44MB disks could not be formatted, at most you could get to 1.2MB, I think it was the same capacity as the 5.25" ones, but I don't remember if we also updated the 5.25" drive.
I think this problem could be solved today (or already is), in practice it could be possible to recognize and format the disks, at a capacity of 1.44MB.
I currently have an MB XT aside, but I have to try which video cards and 16-bit controllers, they work with only 8 bits.

alexthekid wrote on 2025-01-24, 21:09:

I do not recognize a bus controller-IC (like for example a 8288). I assume that this is done by the mysterious M78H1012A in the QFP 100 package:

Acer (or ALI) M1101 chip, used on a few XT motherboards, including Auva MXM/10. https://theretroweb.com/motherboards/?itemsPe … 4&chipsetId=123
Yours is this one: https://theretroweb.com/motherboards/s/auva-computer-mxm-10

Horun wrote on 2025-01-24, 21:28:

alexthekid wrote on 2025-01-24, 21:09:

I do not recognize a bus controller-IC (like for example a 8288). I assume that this is done by the mysterious M78H1012A in the QFP 100 package:

Acer (or ALI) M1101 chip, used on a few XT motherboards, including Auva MXM/10. https://theretroweb.com/motherboards/?itemsPe … 4&chipsetId=123
Yours is this one: https://theretroweb.com/motherboards/s/auva-computer-mxm-10

That was fast. Thank you 😀!

PC@LIVE wrote on 2025-01-24, 21:27:

In the early 90s, we had an XT with a 360 KB 5.25 floppy disk in the office, then the 3.5" 1.44MB reader was added, and the controller was replaced, unfortunately the 1.44MB disks could not be formatted, at most you could get to 1.2MB, I think it was the same capacity as the 5.25" ones, but I don't remember if we also updated the 5.25" drive.
I think this problem could be solved today (or already is), in practice it could be possible to recognize and format the disks, at a capacity of 1.44MB.
I currently have an MB XT aside, but I have to try which video cards and 16-bit controllers, they work with only 8 bits.

Thank you for your reply. Well the 8272A is soldered onto the motherboard. Per its datasheet it only supports DD. I dont know if I can simply add another FDC-Controller (will try) or if I need to disable the onboard controller first.

Acer (or ALI) M1101 chip, used on a few XT motherboards, including Auva MXM/10. https://theretroweb.com/motherboards/?itemsPe … 4&chipsetId=123
Yours is this one: https://theretroweb.com/motherboards/s/auva-computer-mxm-10

I just checked the retroweb-link. Unfortunately no manual but at least I know model and manufacturer. Also it seems that I have a different bios version. I will upload my bios here shortly.

Just a quick observation: The jumpers for IRQ are for the two com the ports. The headers back of board are KeYLOck, WHL most likely Turbo switch, HRS reset, POLD power led, SP most likely speaker, LED1 Turbo LED.
You probably already figured those things out but thought would mention them (based on my limited knowledge of other odd marked old XT's but could be wrong on some).....
The Acer M1101 is rumored to be a UMC 82C088 which there is a datasheet....
Also if you look at this: https://theretroweb.com/motherboard/manual/su … 89973548962.pdf
page 20 appendix gives short M1101 description....

added: thanks weedeewee yes think ctrl-alt-+ or - change speed

Just an fyi, the m1101 turbo switch function is only read upon bootup or reset. changing the state during normal operation is only possible either via writing to the correct io port or, if bios supports it, the right key combo, like ctrl-alt-num-