PC - Osborne LP4S-25C motherboard recognition for CPU upgrade

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Hi, I've been collecting oldschool hardware before but I just recently bought my first oldschool PC, Osborne LP4S-25C.

I've been trying to recognize what motherboard this PC uses but I can't seem to figure it out. I search long and hard, and I had no success. I tried searching both http://motherboards.mbarron.net/ and http://stason.org/TULARC/pc/motherboards/index.html#.UZPoYfEvl2M motherboard resources, I also emailed the company that owned at time and still does own the Osborne trademark for information, they didn't even know they've produce such machines nor did they have any information for such boards.
The board has the following chips:
OPTi 82c392
OPTi 82c495
Chips P82c206
Cache uses: Motorola M6264cp26
BIOS: AMI bios
Graphics chip: Western Digital 379-C009-R0

Here are some pictures of the board:
PICTURE1
PICTURE2
PICTURE3
PICTURE4
PICTURE5
PICTURE6
PICTURE7
PICTURE8
PICTURE9
PICTURE10
PICTURE11
PICTURE12
PICTURE13
PICTURE14
PICTURE15

Maybe you can help me?

I'm going to upgrade my 486SX(5V) to a 486DX2(3V) and I guess I'd have to change some jumper settings if I want to change the voltage of the CPU socket, so knowing the motherboard name and jumper settings would be a smart thing to do.


Thanks!

 

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I got email from the company that produced this maching,
Apparently this machine was a rebranding of a Wang Slimline Alliance 750CD 486. But they weren't able to tell what motherboard this system uses. I tried googling this machine but I didn't get any success finding what motherboard 750CD uses...

 

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roughly translated they said,

Manufacturer of the motherboard is probably Wang.
I found one link ( even though this is a 386 model )
http://ancientelectronics.wordpress.com/2012/11/03/wang-alliance-750cd/

the 486sx model went with the name slimline Alliance 750CD

Now the case of the Wang alliance 750CD looks the same as a Osborne LP4S-25C, but the Wang machine uses a 386 motherboard. There are no pictures of the slimline Alliance 750CD computer and little information so if any of you know anything about Wang 486 machines that might help...

 

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still no idea which motherboard this system uses but I'm happy to inform that I've upgraded the CPU successfully. So I'm considering this thread done...

btw. the motherboard detects 3.3V cpus, no need for jumper trickery...