[comp.sys.ibm.pc.hardware] Sources for 386 motherboards?

darrylo@hpnmdla.HP.COM (Darryl Okahata) (09/10/90)

Hi,

     I need to replace the 386 motherboard in my lunchbox transportable, and
I'm finding difficultly locating a motherboard that meets my requirements (the
inside of the case is very cramped).  Does anyone know of a 386 motherboard
with the following specifications?

Absolute requirements:

1. Must be an XT-sized motherboard.  An AT-sized motherboard will not fit
   in the case.

2. The 386 should be running at either 20- or 25-MHz (either-or -- not
   both).  A cache is desirable, but not necessary.  Also, the 386 must be
   a 32-bit 386; a 386SX will not do.

3. Must be expandable to at least 16-megabytes of 32-bit RAM (using 16-bit
   RAM is not acceptable).  It is preferred that the memory be on the
   motherboard, although it can be on a special 32-bit RAM card.  It would
   also be nice (but not necessary) if the memory used SIPPs and not SIMMs,
   as I already have SIPPs.

4. Expansion slots #1 (the slot furthest away from the power supply, and
   the one closest to the edge of the motherboard) and #2 must both
   be 16-bit slots, unless slot #1 is a special 32-bit slot for a RAM card,
   in which case slots #2 and #3 must both be 16-bit slots.  Full-length
   16-bit cards must be able to fit into these slots.

5. The expansion bus must run at 8 MHz.  The expansion bus must not be run
   at 10 or 12.5 MHz; it must be run at 8 MHz.

6. The motherboard must be able to run MSDOS and Unix.

7. There must be support for a 387 coprocessor.

Does anyone know of a motherboard that meets these requirements?  Any help will
be appreciated.

     -- Darryl Okahata
	UUCP: {hplabs!, hpcea!, hpfcla!} hpnmd!darrylo
	Internet: darrylo%hpnmd@hp-sde.sde.hp.com

DISCLAIMER: this message is the author's personal opinion and does not
constitute the support, opinion or policy of Hewlett-Packard or of the
little green men that have been following him all day.

Robert.Berry@samba.acs.unc.edu (BBS Account) (09/10/90)

Darryl, the motherboard I bought for the 386 system I built (and am now using)
is a Chicony 386-20.  I believe it meets most of your requirements quite well.
	
1. It is XT-sized.

2. It runs at 20 MHz and is a 32-bit 386DX.  (No cache, though.)

3. It is expandable to 8 meg on the motherboard and an additional 8 meg
   on a proprietary 32-bit expansion card.  (Takes SIMMs instead of SIPPs,
   I'm afraid.)

4. Slot #1 is a 32-bit slot for the RAM card; 2, 3, 4, 5, and 6 are 16-bit
   slots.

5. I am not certain about the bus speed, but I have encountered no compat-
   ibility problems so I assume it is the standard 8 MHz.

6. DOS runs fine, as does Win3, so protected mode works.  I have not ever
   tried Unix, though.

7. 387 coprocessor is supported.

I have been very happy with the motherboard.  Despite the fact that my system
is 100 % clone technology and was put together by an amateur, I have never
had a single problem with it.

--
***********************************************************************
Rob Dale                        =   Rob.Dale@bbs.acs.unc.edu
8-7 Ross Ade Dr                 =
W Lafayette, IN  47906          =   tippy!rdale@newton.physics.purdue.edu