Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!vaxphw.dec.com!phil
From: phil@vaxphw.dec.com (At 'MACS'imum efficiency!)
Newsgroups: comp.sys.mac
Subject: Is my INTERNAL SCSI port dead?
Message-ID: <8809281351.AA27458@decwrl.dec.com>
Date: 28 Sep 88 13:51:28 GMT
Organization: Digital Equipment Corporation
Lines: 52

Hello all,

Well, here is a REAL strange problem.......First, let me explain my
configuration.  I have a Mac II with TWO disk drives connected to the INTERNAL
SCSI connector (the 50-pin connector).  One is AN APPLE 80MB and the other is a
Maxtor XT-2190 connected to the Adaptech 4070 board. The Apple uses the
internal power supply and the XT-2190 uses an external power supply, but they
are both connected to the same power strip, no ground differential....It looks
like this:

                             +------------------------[===]--------------+
                             |Mac II Case           Externl              |
                  +-----+    |                      SCSI DB-25           |
     +-------+    |     |    |  +---------+                              |
     | Maxtor|    |Adap-|    |  |Apple 80 |                              |
     | XT2190|    |Tech |    |  |SC intrnl|                              |
     |       +----+4070 +-------+         +-----[===] Internal           |
     |       |    |cntrl|    |  |         |           SCSI 50-pin        |
     |       |    |     |    |  |         |                              |
     +-------+    |     |    |  +---------+                              |
                  +-----+    |                                           |
                             |                                           |
                             +-------------------------------------------+

I made my own 50 pin SCSI connector with 3 sockets on it to connect to the
Mac II, the Apple  Drive, and the Adaptech 4070 controller board.  Note:  I 
did NOT remove any terminators.  When I tried to remove any of the 3 resistor 
packs on the Apple 80mb drive, it did not work, giving a Sense error or 
something...

Everything worked perfectly for 3 weeks now.  I turn on the external XT-2190,
then power on the Mac, it waits for the disk to finish spinning up and then
boots it. Great!!!

It worked fine up to last night.  It worked, I powered it all down and came
back later to do some more work.  I powered up the MAC first by accident and
then switched on the XT-2190.  The Mac booted the Apple 80mb.  I said 'Fine,
it didn't see the XT-2190 quick enough'.  But then the Finder didn't mount it
although I saw the disk access light come on and off 2 times.  So I installed a
new driver to the XT-2190 with no problem, Finder still doesn't see drive.  I
run the CDEV SCSI Tools by P. Mercer to mount disks, it sees the XT-2190 at
SCSI Id=1, but crashed the Mac when I hit the MOUNT button.

I reboot, get the standard chime, then when the XT-2190 comes up to speed, I
see one disk access and then the Mac does a 4-CHIME in-a-row, each a higher
note then the previous chime sound and goes to a dark blue screen and sits 
there.  If I boot a floppy, the 'Welcome to Macintosh' message appears, but as 
soon as the XT-2190 comes up to speed, the 'Welcome' box starts flickering....,

HELP!!!  What happened?????

Phil Hunt