My guess is your board is an
OrangePC 210 or
220, based on lack of PCMCIA, slower CPU and inclusion of serial/parallel port via octopus cable. You won't need the dongle to get it running since it routes video through the Mac.
You can see my OrangePC 250 earlier in this thread, it has a big transistor below the jumpers and a PCMCIA slot and its a DX2/66. Note even after I swapped in a DX4 overdrive and changed jumpers it didn't go any faster so maybe don't worry about the jumpers and just set it to what 486 you have on it.
You can also see
@Unknown_K's OrangePC290 card earlier in the thread which has a big voltage regulator for the DX4/100.
The later OrangePC 340 has a
different board layout with more vram and 5x86 processor and the earlier Orange386 has an ISA slot. I haven't been able to find many/any pics of the OrangePC 210/220 so if you can take nice high res ones that might be helpful for posterity.
As far as software to get them to work, my machine is in storage so I can't help. I remember it being relatively straightforward though, but a pain to swap all the Windows floppies
If its not showing up in TattleTech it isn't a software problem tho. First you want to make sure your power supply can give it enough juice. Next you might want to look at replacing the capacitors (these have several tantalums on them). Finally, consider swapping some of the chips, which is of course the most work. My board seems to have some VRAM problem that I mention on page 1 that causes it to crash after a while, so extrapolating from my anecdote its possible these cards may have chips on them that aren't super great.