Date   : Tue, 14 Mar 2006 20:56:13 +0000
From   : Fragula <fragula@...>
Subject: Re: 1MHZ SCSI/ATA board

Howdy Phil!

Phil Blundell wrote:

> Excellent.  Yeah, I think both (!) my 80286 boards have CPUs fitted;
> they're just missing the RAM and ROMs.  I'm guessing that it wants 32
> off 41256 for a total of 1MB, or 32 off 4164 for a total of 256K
> (there's a jumper to select the RAM size).  Not sure what clock speed
> they are running at, but 120ns sounds like a good bet to start with.  I
> guess I can always fiddle the oscillator frequency downwards if the RAM
> isn't fast enough.

You've got *two*<rhetorical question mark><mutter><mutter>

Ohh. Don't do that!.. What speed are the CPUs? Rule of thumb, 5 (no
speed marking) and 8MHz=180nS (cause they were about the slowest made)
10 and 12MHz=150nS, 16MHz=120nS There were a few 20MHz and faster rated
286s, but they are just so rare you 'aint likely to have one. (I've met
One, Once. and it was an SMD IIRC, in a "Dan" Mini-PC.) If it IS a 20+ I
have some chips put away that might do the trick. Not sure if I have a
full megabyte tho. Oh.. I might have a Cyrix 80287-10 FPU (the one with
the soldered-back-on pins, barfs at 12MHz.) if you have the socket on
baord to go with it.

Right.. Scanners Elbow, gonna post the URL and get in a nice hot herbal
bath now..

Cheers!

M.