Ok - Im getting very close - but I got yet another question.
As mentioned before there is no documentation available for this board.
My case has a Turbo switch, turbo LED, Power (?) LED, Keylock and a reset button and - most importantly - a good PC speaker.
Reset is the only labeled header on the board and works fine.
There are several additional headers on the board without label. Can anyone make an educated gues what they are fore (see image).
More importantly - if I go back and randomly try plugging things onto those headers - can I break (short) something ?
thanks for the help

JP12 seems to be Turbo Switch.
JP15 - Speaker.
JP14 - Power LED and Keylock.

JP11 and JP13 - Reset Switch and Turbo LED, probe them with a LED first, while toggling the Turbo Switch.

In general, don't probe with switches, as they do total short.
A diode, however, should be safe - no total short.

I'm only wondering why the RESET pins in the middle of the board...
It would be logical to place them in the corner, and it seems that either JP11 or JP13 must be RESET...

The speaker works !
JP13 is indeed a second (?) reset switch and works too.
The rest, unfortunately - seems not working. None of the LED's lights up and none possible combinations is slowing or accelerating the system.
Not sure why this is not working

Thanks for the suggestions

Ok - Im now confronted with a new set of problems. My HDD solution for the machine is a monotech XTIDE card. (XT-IDE Deluxe)
So far this card has worked flawlessly at an 8Bit ISA slot with an (older) very small 128MB CF Card. However, my actual idea is to eventually use a biger drive.
However all larger CF cards dont work properly (I tried 256MB 1GB and 4GB). The problems are diverse yet similar. I usually can partition / fdsik/mbr and install MS-DOS without problems. I also tried to install DOS at another machine. In addition I tried Phils boot disk. The PC then boots sometimes. If it boots the drive is always corrupted. As soon as I call a program or a simple command it crashes. Sometimes it continuously executes garbage and fills the screen with messages or symbols. Sometimes it tells me that a fle is corrupted. Checking the files on another machine shows them ok. Sometimes I can even run a program. For example Prince starts sometimes, but then asks to insert a disk into drive C (i.e. the card adapter) and press enter. If I have pressed enter several times it may proceed to level 1 just to finally crash here. So somehow the cards are not properly accesed - as if they are running too fast? or the PC is too slow ? Would be grateful for any suggestions. I know these problems from "normal CF card solutions" but I thought the XTIDE Bios can handle all these problems without issues. Can I change some settings on the XTIDE card to make this work better ?
Thanks

Just anothe error message that just came up was "file allocation table bad"... followed by a bunch of random ASCI characters..."sigh"

Why use the 8-bit XTIDE card if you have the 16-bit IDE card?
BIOS HDD support too limited?

Yes, I have a few small CF cards, but none of the available options fit any of the geometries. On the other hand the XtIDE worked out if the box, but only with small cards.

Im also wondering, to access larger than 504 MB partitions, the bios needs to allow LBA addressing. So is there some configuration of the XTIDE bios required to allow/enable that?

The XTIDE BIOS overrides the 504MB limit of older system BIOSes so you don't need to configure anything in particular (maybe turning LBA on, but I think that's by default). You'll still be limited to what the OS can handle however (partitions of up to 32MB on DOS <= 3.3 or up to 2GB on DOS <= 6.22).

Yes, Im using partitions 2GB or less in Dos 6.22. Also what I think are good quality ("industrial") branded cards. But why would I get such an eratic behaviour? The Motherboard, the XTIDE card or the CF card? What is the most likely source of the problem (remind you a small 128MB card works without problems) Thanks