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Help identify this beauty of 386/486 board

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First post, by ykot

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I have just got a compact AT case powered by this beautiful working board. However, I am quite surprised and unfamiliar with this layout. It seems to be using Cyrix Cx486DLC as CPU and Cyrix FasMath CX-83D87-33 GP as co-processor. In the BIOS it also mentions 128Kb of cache.

Am I correct to think that this is actually a 386 motherboard using 486 processor?

I have immediately unsoldered the barrel battery, which already started to leak acid on one side, and see there is a 4-pin jumper labeled "EXT_BAT", with a jumper in the middle pins of 2-3. What would be the meaning of these pins?

There is also another jumper on right side labeled "JP4" - would be interesting to know what it controls.
By the way, this thing is so small - probably smaller than a Mini-ITX factor. Under one of ISA slots it says "G W386/486 MAIN BOARD".

Edit: updated photo after desoldering barrel battery and cleanup, and attached BIOS dump.

Attachments

  • Filename
    BIOS-2020-06-29.zip
    File size
    42.28 KiB
    Downloads
    43 downloads
    File comment
    BIOS dump from the motherboard
    File license
    Fair use/fair dealing exception
  • motherboard_cyrix.jpg
    Filename
    motherboard_cyrix.jpg
    File size
    635.42 KiB
    Views
    831 views
    File comment
    Photo after desoldering barrel battery and cleanup
    File license
    Public domain
Last edited by ykot on 2020-06-30, 02:04. Edited 1 time in total.

Reply 1 of 10, by Deksor

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I think I've found it : http://www.uncreativelabs.de/th99/m/U-Z/32922.htm
The ext bat connector is to connect an EXTernal BATtery ^^

If it start, can you show us pictures of the POST screen or even better, send us a dump of your BIOS ?

Trying to identify old hardware ? Visit The retro web - Project's thread The Retro Web project - a stason.org/TH99 alternative

Reply 2 of 10, by Anonymous Coward

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Nice 486DLC. It has some pretty unusual OEM markings.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 3 of 10, by Horun

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Yes it is a very odd OEM label, no luck in searches. Wonder who TI built those for, or did they (OEM) just remove TI or Cyrix label and add their own logo.... curious !

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 4 of 10, by cyclone3d

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Looked up CDCOM International Inc. and it looks like they were an importer and reseller.

Seems they had a shipment of VGA cards seized in 1996 by US customs due to the mfg having a counterfeit MS logo on them:
https://books.google.com/books?id=Q7xrzP4cit4 … %20inc.&f=false

https://www.corporationwiki.com/Florida/Miami … nc-4370769.aspx

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 5 of 10, by ykot

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Thank you for identifying this motherboard, I really appreciate it.

I have edited my initial post with BIOS dump and updated the photo. I am attaching here BIOS startup screen and some benchmarks. I couldn't run CCT386 as it would crash with "exp overflow", similarly HWINFO would crash with "exp overflow" during FPU benchmark. SpeedSys takes too long to benchmark CPU so I'll run it later. Curiously, NSSI identified FPU as "Internal Emulator"?

By the way, on the aforementioned web page with the jumper information, chipset is described as "unidentified", but looking at some chips it seems to be UMC.

Edit: it looks like these benchmarks were performed with NPU disabled by JP7 jumper, enabling it eliminates CCT386 and HWINFO crashes and improves NSSI - FPU benchmark, I'll upload those later...

Attachments

  • nssi_fpu.jpg
    Filename
    nssi_fpu.jpg
    File size
    309.88 KiB
    Views
    831 views
    File comment
    NSSI - FPU benchmark
    File license
    Public domain
  • nssi_cpu.jpg
    Filename
    nssi_cpu.jpg
    File size
    355.59 KiB
    Views
    831 views
    File comment
    NSSI - CPU benchmark
    File license
    Public domain
  • nu_benchmark.jpg
    Filename
    nu_benchmark.jpg
    File size
    217.54 KiB
    Views
    831 views
    File comment
    Norton Utilities - CPU benchmark
    File license
    Public domain
  • bios_screen.jpg
    Filename
    bios_screen.jpg
    File size
    257.66 KiB
    Views
    831 views
    File comment
    BIOS startup screen
    File license
    Public domain

Reply 6 of 10, by evasive

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Amptron DX-5800 aka PCChips M3** (previously thought to be the M326 but that has a different layout and chipset).

Here's another (Amptron/PCChips) CDCOM offering in another thread:
M396F motherboard

Reply 8 of 10, by ykot

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Thanks a lot! This has been running great so far, very fast and stable. I have ordered an AMD 386 DX/40 along with its co-processor (which already arrived) to try with this motherboard and see how it performs in comparison to Cyrix.

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