I have some 486 motherboards, about four or five are working, all VLB, but I have as many to test (and repair), I don't know if you're interested, I'll put a couple of images, of the last two, which I should test soon (if they work) Unfortunately, at the moment I don't have a BIOS screen, nor can I make a copy of the BIOS (stored in the chip), but if you want I can make a list with the manufacturers and models of 486 that I have.

PC@LIVE wrote on 2023-12-26, 08:59:

I have some 486 motherboards, about four or five are working, all VLB, but I have as many to test (and repair), I don't know if you're interested, I'll put a couple of images, of the last two, which I should test soon (if they work) Unfortunately, at the moment I don't have a BIOS screen, nor can I make a copy of the BIOS (stored in the chip), but if you want I can make a list with the manufacturers and models of 486 that I have.

Image

#: 162
Manufacturer/Identifier: SOYO 025K0
Chipset: 85C407 , 85C471
BIOS/Version: AWARD
BIOS ID : 09/26/94-SIS-85C471B/E/G-2C4I9S23-00

Images : W27C512

#: 163
Manufacturer/Identifier: UM4981AIO V1.3
Chipset: UM8498F , UM8672F , UM8496F , FDC37C665GT , UM82C865F
BIOS/Version: PHOENIX
BIOS ID : ???

Images : W27C512

#: 164
Manufacturer/Identifier: TANDON C747
Chipset:
BIOS/Version:
BIOS ID :

https://theretroweb.com/motherboards/s/caf-te … ,-c747-ver.-002

Zalog wrote on 2021-04-07, 13:01:

Yes unfortunately it requires a fair degree of disassembly - fortunately I took one in the middle of an upgrade so if you don't […]
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evasive wrote on 2021-04-07, 12:36:

@Zalog: Could you make a picture without the metal support in the middle? Or does that require full disassembly?

Yes unfortunately it requires a fair degree of disassembly - fortunately I took one in the middle of an upgrade so if you don't mind shots of it that are slightly less clear (a bit harder to read the chips at the VGA end of the board) and in non-original condition (added cache chips, overdrive + extra ram) - find attached

PC9486_Upgrade.JPG

Edit: BIOS String is: 40-0100-001131-00111111-111192-UMC480

Hi.

does your L2 cache work with the Pentium OD cpu ?
cant get mine to work with L2 with a 486DX2 cpu it works perfect.

#: 165
Manufacturer/Identifier: Shuttle HOT-419 VLB
Chipset: OPTi 82C895
BIOS/Version: AMI Winbios
BIOS chip: ST M27C512

https://theretroweb.com/motherboards/s/shuttle-hot-419

#: 166
Manufacturer/Identifier: PCChips M912 Ver. 1.4 (this one is with real cache chips)
Chipset: UMC UM8498/8496 (486 VL Chipset "Super Energy Star Green") (CHIP16/CHIP18)
BIOS/Version: AMI + Award BIOS (combined into one 1 Mbit (128 kB) EEPROM*)
AMI BIOS ID: 40-E300-001437-00111111-121593-GREEN-H
AMI BIOS Sign-on: Release 07/08/1994
Award BIOS ID: 07/13/94--2C4X6H01-00
Award BIOS Sign-on: Release 07/15/94'

AMI BIOS:

Award BIOS:

AMI + Award BIOS combined into one 128 kB image*:

*- AMI or Award BIOS is selected by jumper JP2: 1-2 or 2-3 pins shorted. Short 3-4 pins of JP1 (ext. batt. connector) to clears CMOS when switching BIOSes through JP2!