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Intel iSBC386AT, iSBC386AT/25, SYP301, SYP301Z, & SYP302 AT Compatible 386 Boards

willmurray461

Experienced Member
Joined
Jun 11, 2018
Messages
285
Location
Boca Raton, FL
I recently got an Intel iSBC386AT motherboard and a NOS Intel PC case w/ power supply to go with it. I even found two of the proprietary Intel iSBC386MEM020 2MB 32 bit ISA memory expansion cards! Hopefully I can create a working system soon. However, there is pretty much no documentation on the internet for these boards other than magazine articles and advertisements. Documentation would be helpful for setting up things like the onboard serial and parallel headers and help demystify what the dozens of jumpers do.

This is the information I've gathered so far:

Apparently, the motherboard I bought is called the Intel iSBC386AT, which is one of, if not the first IBM AT compatible 386 motherboard. There was a complete PC offered by Intel that uses the iSBC386AT called the SYP301. There's also a motherboard called the iSBC386AT/25A which is completely different, and the complete system with an iSBC386AT/25A is called the SYP302. On top of that, there's the SYP301Z (I don't know what the motherboard by itself is called), which is similar to the SYP301, but features zero wait states, hence the suffix "Z". There's also an SYP301X, which is the same as the SYP301 but with "less features." The iSBC386AT has a 16MHz 80386DX, 512KB of onboard memory, eight ISA slots (two 8bit, four 16bit, two for proprietary 32bit memory expansion bus which are 8bit backwards compatible), and a slot for a math coprocessor. From what I've read, early models of the iSBC386AT did't support the 80387, and had to use a 80287 with a special adapter board. This was fixed in later revisions (circa late 1987?). I have no idea what the motherboard in the SYP301Z or SYP301X looks like, but I'm assuming it's pretty much the same as the iSBC386AT. I know for a fact that they all have a 16MHZ CPU. The successor to the iSBC386AT, the iSBC386AT/25, is pretty well documented however. The technical reference manual is available online under the name "Intel System 302 Technical Reference." The iSBC386AT/25 has a 25MHz 80386DX, 1-8MB of onboard memory, 64KB of built in cache, eight ISA slots (one 8bit, five 16bit, two for the AT32 bus interface, another 32 bit memory expansion bus which is 16 bit backwards compatible), and a socket for the 80387. On top of that, the iSBC386AT/25 has onboard SIMM sockets which can be used to expand memory, unlike its predecessor. Intel also offered memory expansion boards for their proprietary 32 bit expansion slots, along with a few third parties. The Intel memory expansion boards for the iSBC386AT are called the iSBC386MEM020 and iSBC386MEM080 which add 2MB and 8MB of 32 bit addressable memory respectively. An Intel memory expansion board for the iSBC386AT/25 is also mentioned as the "ATEM8" and I assume it adds 8MB from the name.

iSBC386AT (early version with special 80287 board):
$_57.jpg

iSBC386AT (later revision):
s-l1600.jpg

iSBC386MEM020:
s-l1600-7.jpg

iSBC386AT/25:
s-l1600-2.jpg

Generic Intel PC Case:
s-l1600-3.jpg
s-l1600-4.jpg
s-l1600-6.jpg
s-l1600-5.jpg

Sources:
https://books.google.com/books?id=J...Q6AEIODAD#v=onepage&q=intel iSBC386AT&f=false
https://books.google.com/books?id=P...kKHc7_D14Q6AEISDAG#v=onepage&q=syp301&f=false
https://books.google.com/books?id=b...ved=0ahUKEwij5vrSvafgAhXyuFkKHauEBlMQ6AEIVDAJ
https://archive.org/details/PC-Mag-1988-01-26/page/n131
https://drive.google.com/file/d/1NP23Cja9fXL_tqk3Y5SPXQZHzkH7nv4w/view?usp=sharing
https://drive.google.com/file/d/1ClJlxRXhz7TAUDDYY34d0wchzD0l_5zj/view?usp=sharing

Anyway, the main reason I made this post is to ask for help. If there's anyone out there who knows anything about these systems, perhaps by seeing them back in the day or working with them, please share your info. Also, if anyone has any Intel documentation relating to the Intel SYP301, please try to scan and archive it, as there is no official Intel documentation on the internet at all.
 

Al Kossow

Documentation Wizard
Joined
Sep 1, 2006
Messages
2,741
Location
Silicon Valley
I recently got an Intel iSBC386AT motherboard

Anyway, the main reason I made this post is to ask for help. If there's anyone out there who knows anything about these systems, perhaps by seeing them back in the day or working with them, please share your info. Also, if anyone has any Intel documentation relating to the Intel SYP301, please try to scan and archive it, as there is no official Intel documentation on the internet at all.

These Intel products were from when they bought Bell Technologies.
I have a few manuals up under bellTechnologies on bitsavers

I also think Everex sold a version. They had a mb that looked very similar incl the memory expansion slots.

Intel OEMed these machines to Daisy for the Personal Logician.
They were also used in the iPSC multiprocessor cube as the control computer.
 

Chuck(G)

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Jan 11, 2007
Messages
38,896
Location
Pacific Northwest, USA
I think I've got the Everex version, 20MHz 80386. No memory on the planar, with 13MB(!) on a memory expansion card. NDP is a 40 pin DIP socket.
 

Al Kossow

Documentation Wizard
Joined
Sep 1, 2006
Messages
2,741
Location
Silicon Valley
I think I've got the Everex version, 20MHz 80386. No memory on the planar, with 13MB(!) on a memory expansion card. NDP is a 40 pin DIP socket.

A photo would be cool. Looks like he's going to need the bios eproms

https://books.google.com/books?id=PA3RA3f6mi0C&pg=PA41
mentions some of the companies that were OEMing intel mbs

'vanderk'
http://www.vcfed.org/forum/showthread.php?44055-WTB-386DX-or-SX-Computer-(desktop-or-tower)&p=336691
mentioned he had one here in 2014
 

willmurray461

Experienced Member
Joined
Jun 11, 2018
Messages
285
Location
Boca Raton, FL
If anyone is interested, I found this document which somewhat briefly details all of the intel motherboards described earlier in the thread:
Chapter 1 of Intel's OEM Boards and Systems Handbook 1989:
http://bitsavers.trailing-edge.com/...Books/1989_OEM_Boards_and_Systems_Hanbook.pdf

Also, my intel iSBC386AT Board which I bought from eBay unfortunately doesn't work. When I turn the system on, the power supply turns on, and the front power led also turns on, but no activity happens. Video cards show no video, FDD/HDD controllers do nothing, and the case speaker doesn't beep either. The chips on my video card become warm and so does the CPU, so I can tell that the board is probably not having issues with power. I think there might be a problem with the BIOS chips, as the symptoms seem to match. It could be the jumpers, but I compared my jumpers to those on mR_Slug's iSBC386AT board on his post from a while back and they seemed to be the same. Does anyone know if I could try to find replacement BIOS chips that are compatible with this motherboard? They are Phoenix Technologies bios chips.
 

willmurray461

Experienced Member
Joined
Jun 11, 2018
Messages
285
Location
Boca Raton, FL
I don't have an EPROM reader/programmer. I was thinking about buying one, but they're kind of expensive and I don't know which one to buy.
 

willmurray461

Experienced Member
Joined
Jun 11, 2018
Messages
285
Location
Boca Raton, FL
There are, but I don't know if they're any good. The ones I was told were worth buying were $75-$100. I would consider buying one if it was ~$50. Also, unfortunately, I don't have any other 386 motherboards besides an IBM 8580, which I don't think will take them. I probably should buy an eprom programmer anyway because I wanted to make some copies of the XTIDE bios for my IBM AT.
 

SHUTNIK

New Member
Joined
Sep 16, 2016
Messages
4
There are, but I don't know if they're any good. The ones I was told were worth buying were $75-$100. I would consider buying one if it was ~$50. Also, unfortunately, I don't have any other 386 motherboards besides an IBM 8580, which I don't think will take them. I probably should buy an eprom programmer anyway because I wanted to make some copies of the XTIDE bios for my IBM AT.

How are you doing with BIOS copying? Have you solved the problems with starting the board?
 

willmurray461

Experienced Member
Joined
Jun 11, 2018
Messages
285
Location
Boca Raton, FL
I've programmed the BIOS I found online (Which is 128KB, as opposed to my original 64KB bios) into an EPROM, but it hasn't solved any problems. Although I might have the jumper settings for setting BIOS size wrong...
 
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