Re: Need help hooking up old SCSI drives

[mjmahon@aol.com (Michael J. Mahon)]

colin_tokyo@hotmail.com  (Xerxes409) wrote:

>I need to mount one (of two) old SCSI hard disks inside an external
>case so I can use it alongside my old Apple IIGS. The plus side is I
>have a Seagate and a Quantum ready for use; the bad side is I have
>zero idea where to hook up the two wires for termination and the
>power/read LEDs. Despite the fact that the pinouts are printed on the
>drive itself, I am too stupid to figure them out (hangs head in
>shame).
>
>However, I took pictures and put 'em here:
>http://www.tokyopia.com/colin/oldhdds/thumbs_d/thumbs_p.html
>
>Can someone tell me just where (and IF it's possible to) to stick the
>two sets of cables? I really do need to be able to manually set
>termination because it's gonna be one of several devices on a chain.

First, some terminology:  termination is quite different from device ID,
which you need to set manually.  Termination can be proficed (resistive)
or not, and termination power (+5v) can be provide or not.

External (or at least switchable) termination is always a good idea if a
device will not be the last device in a chain.

The SCSI ID is set by three spst switches, often combined in a
little assembly that displays a single digit ID number, with pushbuttons
to increase or decrease it.  If an ID bit is grounded, it is a "1", otherwise
it's a "0", and the three bits (ID0, ID1, ID2) are the binary ID number.