Oh thats really interesting! Thanks on the confirmation and that revision number as well! I definitely have never had a chance to look at a motherboard from that era in person before this one, so this is definitely great to know that this is indeed a Chaintech product.
I did look for a specific "Identify this motherboard" thread before opening this one, so I third for a dedicated sticky for these (with a separate one for expansion cards....and I guess input device and monitor ones too). I can't really say I found these in the dumpster or bought these either 😀
giantclam wrote on 2023-09-20, 03:39:
Even the chaintech boards were 'unmarked' (referring to the silkscreen printing) ~ the only real identifier was a sticker or 2 either on the board itself, or on one of the ISA slots.... a lot of the time these stickers came off (or ppl removed them as they were falling off) ; sometimes you can see evidence of glue residue that's a telltale something like this happened.
There are in fact 2 stickers on the bottom of the last ISA slot one is a silver AWARD BIOS sticker, and the other one next to it is a serial number S/N: M9811XXXXXX (unsure if I'm allowed to post whole serial numbers here like that).
PcBytes wrote on 2023-09-20, 08:35:
My biggest giveaway for Chaintechs of this era is the dotted pattern throughout the board.
That, and in certain cases, the strange header used for USB on some of their socket 7 mobos.
Those dotted line etchings actually look really cool. They all seem aligned to a different line of each bus. It probably makes probing the intel chips much, much easier.
giantclam wrote on 2023-09-20, 11:10:...two things I noticed.... […]
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...two things I noticed....

...that wouldn't make sense on a 6BTA2 ...it does make sense on a 6ESA or 6LTM but this board is definitely 6BTA2 sku.... and one of the key differences here is chipset -- intel 440 BX/EX/LX ....
Good eye, I did not look that much into the details yet.
giantclam wrote on 2023-09-20, 11:10:..which makes me look twice at this... […]
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..which makes me look twice at this...

...errm.... since when would discovering a/the chipset part number, constitute voiding warranty? I could understand putting a sticker on the yamaha chip to obfuscate it's identity. but not that.... to me, it makes me think they're hiding something ... boot up linux and see what it finds (if you're attest to removing stickers =)
I want to say that sticker is there as a (cheap) way for the server vendor to deal with scams from product returns. Someone would have a broken motherboard, buy the new one from the vendor, then return the broken one to get their money back. I hear about that type of thing in the state where I live pretty often (not just with computers), and I do think it's pretty sad that some vendors have to set up different little measures to circumvent that.
I am definitely going to run linux on all these machines and test everything out. I just am not sure how soon that will happen, I'm in the middle of a major data storage management overhaul where I live and I kinda want to knock that out of the way before I dive further into these motherboards.
PcBytes wrote on 2023-09-20, 11:20:It is present on other 6BTA2 boards. Check this photo I found from a bay listing. M101 marking in the same spot, and also no CT/ […]
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It is present on other 6BTA2 boards. Check this photo I found from a bay listing. M101 marking in the same spot, and also no CT/Matsonic markings, just like OP's board.

So to answer to the topic - OP, your board is a 6BTA2-H103N to be exact. The only things I can explain about the different tag instead of 6BTA2-H103N, is that the company that made the servers might have requested the specific text in place of the actual model.
Nice find! That example definitely clears up the exact model number of the motherboard. And we both suspect the same thing with the label on the BIOS chip. "ATX-AUDIO-2" itself could be how the server vendor marketed this board in their catalog/website/etc. Where I live, there used to be a place called TigerDirect, and I did check the archive of their website just in case this was one of their store brand motherboards, but I don't think it was them. I'm not sure who specifically sold servers down here back then. Finding the actual motherboard manufacturer, model number, and revision is good enough though.
Thanks for all of your feedback everyone!