wbahnassi, your motherboard tries to boot with prompt to enter BIOS settings because of non-working videocard error. That's why you hear 2 more short beeps after the Award BIOS sound error pattern for videocard problem (1 long + 2 short beeps) and some "interval" of silence.

One short beep is when mobo POSTs normally (without errors) and it's weird to hear this when there's still non-working videocard.

As for the BIOS strings - you have to merge (deinterlace) the low + high dump files into one file and then you can see all the strings in the BIOS with any hex-editor.

wbahnassi wrote on 2025-07-02, 16:56:

[*]MDA card (8-bit) - No progress

So you did try a dumber card and it still didn't work. Then I guess there might be some damage. Things to try:
- Connect and use RESET button, in case the mobo doesn't init properly for some reason on power-on.
- Make sure the 146818 RTC chip is getting power from PSU, if there is any battery corriosion in that area it migt be unpowered and that will cause havoc.
- While testing the RTC see if you can draw some basic schematic of the connections to the battery header. Some of these mobos require a jumper for external battery for example. IIRC I once ecountered a mobo that needed it for the on-board battery as well, except on different pins. But missing jumper should not prevent the RTC chip being powered from PSU.

And finally there is usually ALS245 chip near the ISA slot and the RTC and KBC. It's a bi-directional driver for the lower 8 bits of the ISA bus, and it often dies (usually not completly, one or more bits get weak or stuck). This will prevent the mobo from being able to talk to any of the cards, and even detect the video memory. You might want to desolder it and put a socket there. If the chip is good it can be socketed, if not you can replace it with ALS or ACT series. Note it's sometimes very hard to figure out the bad data bits if the output is just weak, so consider the socket if you don't fancy in-depth logic probing of the ISA signals.

wbahnassi wrote on 2025-07-02, 16:56:

What tool did you use to extract that string? Looking straight at the files in a basic binary viewer didn't yield anything human-discernible to me.

Chipset on these mobos is not all that advanced, it's basically just a bunch of PLDs with a lot of pins to handle all the busses and signals. So there is no ROM shadowing and EPROMs are slow, so for 286 you want at least to make up for it with 16-bit wide data. So each of the BIOS ROMs is one byte wide, the EVEN is bits 0-7 (so bytes 0, 2, 4, etc) and ODD is bits 8-15 (bytes 1, 3, 5, etc). To get proper ASCII strings you need to combine both dumps to get what the CPU actually sees. I've attached the result of that in the previous post.

Okaaay, so.. then does that mean I need to reverse this BIOS interleave process before I burn the ROMs? Because so far I have been just downloading BIOS files that have LO and HI parts and directly write each to a chip.. but many other ROMs came as one combined file.. so I need to split that or what? And what tool do I use to split it?

wbahnassi wrote on 2025-07-02, 22:59:

does that mean I need to reverse this BIOS interleave process before I burn the ROMs? Because so far I have been just downloading BIOS files that have LO and HI parts and directly write each to a chip.. but many other ROMs came as one combined file.. so I need to split that or what? And what tool do I use to split it?

Yes, if you get an image obtained via software read, or an alaready combined file for whatever reason, you need to split it to EVEN/ODD byte parts to burn it into EPROMs. These mobos would always have 2 EPROMs so there should be two files, but some newer 286 mobs (with 20MHz+ CPUs) will have chipsets that are more like 386SX. Can do shadowing and address more than 4MiB of RAM - so the BIOS ROM will be just one chip, and thus one image file. But good chances are these will not be compatible with this early Suntac "chipset". But you can try splitting it and burning anyway.

What tools to use, well I just wrote my own scripts in Python. Back in the old days I would use QBASIC for that.