Re: Please ID SCSI Card

[dempson@actrix.gen.nz (David Empson)]

Al Boisvert <aboisvert@snac.mv.com> wrote:

> Hi,
> 
> I'm using an Apple SCSI card in my IIGS.  How can I tell if it's a High-Speed
> SCSI or Rev.B, Rev.C, or whatever?

One way to tell is the date on the circuit board: the original card was
made in 1986, the high-speed card in 1990.  (You said '90, so you have
the high-speed card.)

Once you have seen both cards, it is very easy to tell them apart.  The
most noticeable features:

- The original card's SCSI chip (the largest one on the board) is a
traditional 40-pin rectangular DIP, and it is an NCR5380.
- The high-speed card's SCSI chip is a 44-pin square pack chip (PLCC) in
a brown socket, and is an NCR53C80 (the 'C' indicates it is the CMOS
version).  There is a similar looking square pack chip in a socket right
beside it.

- The original card has a row of eight jumpers to set the SCSI ID.
- The high-speed card has a four position DIP switch to set the SCSI ID
(and DMA enable).


To tell the difference between ROM releases on the original card, look
at the part number.

341-0112A    Revision A
341-0112B    Revision B
341-0437-A   Revision C

My original card started with revision A (I still have the original
EPROM), and I upgraded directly to revision C.  I've never had a close
look at revision B, so I'm not entire sure how the suffix is written: it
might be "-B".

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand