Apple HS SCSI card update...

[cjh3@hotmail.com (phunny_fongs)]

I finally got my card working, though most of you probably dont care,
but here me out...

After consulting the a2 FAQ, and figuring out that most of the
problems I was experiencing were symptoms of 'invisible drives', I
promptly decided to make the trm pwr 'mod', this failed and the diode
blow up (thats right, puffs of smoke!).  So I changed tact and moved
to modifying a drive to supply trm pwr.  Not knowing how to do this, I
turned to the a2 FAQ again and it pointed me to the SCSI a2 FAQ.  This
FAQ says that pin 38 on a 50 pin SCSI cable is trm pwr, and pin 25 on
the DB25 cable is trm pwr, so I promptly made the 'mod', tested it,
and nothing!  Not even a blink of a drive light, to suggest anything
was working!

The problem was located to the pinout diagrams in the apple2 FAQ about
SCSI HD etc.  The FAQ says that pin 38 on a 50 pin SCSI cable is trm
pwr, and pin 25 on the DB25 cable is trm pwr, which is correct.  What
the FAQ leaves out is that, AFTER THE 50PIN **CENTRONICS** CABLE IS
PASSED TO THE 50 IDC (on the drive) THE TRM PWR CHANGES TO PIN 26! ! !

See for yourself at:
http://ground.icaen.uiowa.edu/apple2/MiscInfo/Scsi/
look at all the files about hs scsi card.

I think the faq should be updated to reflect this information.
(The FAQ is not wrong, it's just not accurate enough to advise
people.)

So there you have it, and I have a working scsi card!

ch.