Re: Apple IIGS Scsi Woes

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

In article <315ED84E.158B@labtop.com>, Joe Smith  <system@labtop.com> wrote:
> Here's the problem:
> 
> Apple II Scsi card ( original version 1989?)

You'll have to be clearer than that.

The original Apple SCSI card was released in 1986, and the final ROM
revision for it (revision C, labelled 341-0437-A) came out in 1987.
The Apple High-Speed SCSI card was released in 1989 and has never had
a ROM upgrade.

The original card has a large 40-pin dual-in-line SCSI controller
chip, and a row of eight jumpers near the front of the card.

The high-speed card has two socketed 44-pin PLCC (square) chips, and a
set of four DIP switches near the bottom middle of the card.

(You can also look for a date on the printed circuit board - it should
be reasonably easy to spot.)

The jumpers or switches are used to set the SCSI ID of the card (it
should be set to ID 7, which is the jumper pair furthest away from the
edge of the card for the original card, and switches 2/3/4 set in the
lower position (closed) for the high-speed card).

Jumper number 1 on the high-speed SCSI card is used to select whether
DMA (direct memory access) is enabled.  It should be enabled
(down/closed) for highest speed operation (the normal setting),
disabled (up/open) if you have some hardware in the computer which is
not DMA compatible (e.g. any IIe accelerator, some IIgs memory
expansion cards, some other devices which use DMA).

> Quantum LPS 170 MB Scsi HD

My old drive is a Quantum LPS 240, which works fine with both the
original and high-speed Apple cards.

> Whenever I boot with the drive online it just HANGS on prodos screen.

This is the point at which ProDOS asks the SCSI card how many devices
are connected.  There could be a problem with termination of the SCSI
bus, or supply of termination power.  This can cause the SCSI card to
hang while it is trying to search for further devices.

You should have a SCSI terminator connected AFTER the Quantum drive (on
the second connector), OR you should have the termination resistors
installed on the Quantum, but not both.

Assuming the LPS 170 is a similar design to the LPS 240, it will be
supplying termination power, so that isn't likely to be the problem.

Also check the SCSI ID.  The Quantum should be set to SCSI ID 6, which
is the next highest priority (first ID checked when booting).  It
should work fine (but the boot will be a little slower) if it is set
to SCSI ID 0 through 5, but it definitely won't work if it is set to
SCSI ID 7 (the same as the computer).

> I've tried using the modified scsi prodos and same thing.. lockup.

I have no idea what this "modified SCSI ProDOS" is.

> Do I need to upgrade the bios on the scsi card?

"BIOS"?  You use PCs, then?  :-)

If you have the original Apple card, make sure you have the latest ROM
version (as mentioned above).  This should not be causing the problem,
though - the last ROM versions fixed a few bugs, added some more
internal calls (not used by ProDOS), and added support for a CD-ROM
drive.  You must have the revision C ROM to use the original Apple
SCSI card with GS/OS on a IIgs, but earlier versions will work
reasonably well with ProDOS.

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