chem194@canterbury.ac.nz (John Davis, chem dept, UoC NZ) (09/17/90)
I just fitted a 2630 ( 68030 ) board in my 2000 over the weekend,
and I've been experiencing problems with the hard-disk (40mb toshiba
ST-506 interface drive off a 2090a ) ever since.
It'll read fine, and small writes are ok too - but any largish write
will result in a total crash ( typically to guru 03, 04 or 0b ).
I've tried swapping in a different 2090a off a working 2500/30, and
it got rid of the problem - and I noticed the working controller
had the PROM at the rear top of the board ( U36 I think ) marked
as xxxxx-03, wheras as the non-working board was marked xxxxx-02.
Unfortunately the owner of that board kind of wanted it back ... :-)
There's meant to be a replacement HD controller on the way - but what
I'm interested in are ....
- what are the difference between the different revisions of the 2090a
and what does it affect - are there any links, trace cuts etc that should
be done to the 2090a when used with the 2630?
- what other main board alterations should be done for the 2000 when
fitting the 2630 ( my motherboard is labeled rev 4.4 ).
( the board just turned up , no docs on recommended board mods to be
done before fitting etc )
We've tried getting info out of CBM New Zealand, but they either
don't have it, or don't want to pass it on to the dealer I'm going
thru.
Incidentally, the 2090a problem seems related to DMAing into the 32 bit
ram on the 2630 - at least if I set the mask entry in the mountlist to
0xfffff to restrict dma into the 16 bit chip mem it's ok ( then again
that could be due to the slowdown in writes this incurrs ), it's also
okay under the 68000 ....
Any help much appreciated ...
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