[comp.sys.mac.hardware] Help w/SCSI ID# on Apple 20 Meg Drive?

zimerman@phoenix.Princeton.EDU (Jacob Ben-david Zimmerman) (10/15/90)

Hi! I have two questions.  The first is:  I have an Apple (originally
Miniscribe) 20 meg drive taken out of a stock SE.  I am using it in
conjunction with an internal 40meg in a Mac II.  The problem is, I want
the 40 meg to boot first.  How do I set the SCSI ID number on the 20 meg
drive?  The controller says 'adaptec' on it as well as Miniscribe.
There is a plug on the end of the drive with eight pins on it that is
connected to the drive itself by a flat plastic conductor, but I don't
want to make any guesses.

The second question:  I ask the first because the 20 meg won't boot
correctly, and when I try to format it, it says 'drive has hardware
fault, get it repaired.'  This is with Apple's HD setup.  SilverLining
simply says Disk Error and won't format it.  Is there any hope for this
drive? Can it be fixed relatively (<$100) cheaply?  Thanks for any help
you can give.  It does seem to work OK for Data, just not for booting,
so that is why I want it to boot second.  I would guess that it has
munged its boot block area, but I can't tell.

Thanks!

-JBZimmerman!

___________           |-Here comes your father.                        
     ||               |                       -Henry V 
||   ||acob Zimmerman!+> <zimerman@phoenix.Princeton.EDU> INTERNET 
  ===                 |  <zimerman@PUCC>                  BITnet

russotto@eng.umd.edu (Matthew T. Russotto) (10/16/90)

In article <3349@idunno.Princeton.EDU> zimerman@phoenix.Princeton.EDU (Jacob Ben-david Zimmerman) writes:
>Hi! I have two questions.  The first is:  I have an Apple (originally
>Miniscribe) 20 meg drive taken out of a stock SE.  I am using it in
>conjunction with an internal 40meg in a Mac II.  The problem is, I want
>the 40 meg to boot first.  How do I set the SCSI ID number on the 20 meg
>drive?  The controller says 'adaptec' on it as well as Miniscribe.
>There is a plug on the end of the drive with eight pins on it that is
>connected to the drive itself by a flat plastic conductor, but I don't
>want to make any guesses.

I don't know how you change the SCSI ID on the miniscribe, but on the internal
40meg Quantum, you should find some jumper blocks with lines labeled 'A0',
'A1', 'A2'. (underneath the drive) Put jumpers across any one or any two of
these.  Now use Startup Device to make the 40MB one boot first.
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
      .sig under construction, like the rest of this campus.

wiseman@tellabs.com (Jeff Wiseman) (10/17/90)

In article <1990Oct15.234256.26540@eng.umd.edu> russotto@eng.umd.edu (Matthew T. Russotto) writes:
>In article <3349@idunno.Princeton.EDU> zimerman@phoenix.Princeton.EDU (Jacob Ben-david Zimmerman) writes:
>>Hi! I have two questions.  The first is:  I have an Apple (originally
>>Miniscribe) 20 meg drive taken out of a stock SE.  I am using it in
>>conjunction with an internal 40meg in a Mac II.  The problem is, I want
>>the 40 meg to boot first.  How do I set the SCSI ID number on the 20 meg
>>drive?  The controller says 'adaptec' on it as well as Miniscribe.

There should be a set of jumpers on the scsi controller card attached to the
drive itself. I beleive that there are 5 pairs of jumpers. 3 pairs are used to
set the SCSI address, one is to enable a test mode of some kind, and the other
is to enable/disable the "auto park heads after approx. 25 seconds of
inactivity" feature.

Which is which? I forget (I think the scsi pins are the 3 pair towards the
center of the board) but try phoning MINISCRIBE's technical support at
1-800-356-5333. I've had this number a long time but it was still in use last
spring when I needed to contact Miniscribe for the same reason you have.
Also since the 3 pair are adjacent to each other and at one end of the 5 pair,
you may be able to guess by the existing jumpers and knowing what the drive is
currently configured to (probably 0).

Set your internal drive to SCSI id 0 so that I is looked at last for booting.
(if it came already in the machine, it is probably already set to this value).
This allows you to plug an external in and have the external be the drive to
boot first (like overriding the harddisk by plugging in a floppy first). Set
your external to anything other than 0 or 7 (the mac is 7).

Now if you want your internal to always boot first regardless of any external's
presence, open your control panel and (assuming it's in the system folder)
select the "startup device" (or whatever it's called, you know, the one who's
icon looks like a disk). This overrides the natural SCSI address startup order.

>I don't know how you change the SCSI ID on the miniscribe, but on the internal
>40meg Quantum, you should find some jumper blocks with lines labeled 'A0',
>'A1', 'A2'. (underneath the drive) Put jumpers across any one or any two of

Just an item of interest. The Quantum 40's are one of the drives that can have
their scsi id's changed via software. Silverlining allows you to set the scsi
id of one of these drives to a value of 0-6 OR "jumpers". This wasn't really
well documented in their manual and I stumbled on it one day when I thought
that I had screwed up my scsi bus! Since I use Silverlining EXCLUSIVELY on my
drives (oh you poor souls still relying on Apple's software :-) :-) I now have
the capability of putting another device on my scsi chain and changing the ids
to be compatable without needing a screwdriver (not mention all the other neet
tricks. Now if I can just get around to sending in for my almost free update I
will be able to use their new graphical disk optimizer).
 
Oh, and one last thing. If that Miniscribe was stock in a new mac at one time,
it is likely set to id 0 already. I believe that means there are NO jumpers to
be moved, only added. These are special low profile type jumpers that you could
probably get at an apple service center somewhere. You will need 1 to set id's
1,2, and 4, you will need 2 for 3,5, and 6.

Hope this helps!



--
Jeff Wiseman:	....uunet!tellab5!wiseman OR wiseman@TELLABS.COM

davisson@milton.u.washington.edu (Gordon Davisson) (10/17/90)

In article <3349@idunno.Princeton.EDU> zimerman@phoenix.Princeton.EDU
(Jacob Ben-david Zimmerman) writes:
>Hi! I have two questions.  The first is:  I have an Apple (originally
>Miniscribe) 20 meg drive taken out of a stock SE.  I am using it in
>conjunction with an internal 40meg in a Mac II.  The problem is, I want
>the 40 meg to boot first.  How do I set the SCSI ID number on the 20 meg
>drive?

This is a MiniScribe 8425SA, right?  (There should be a label on the HDA
somewhere)  I don't have any official documentation, but empirically...
Find the largest square surface-mount chip on the controller board (near
the SCSI connector).  Beside it is a 2x6 array of header pins sticking
up from the board.  The three pairs of pins nearest the SCSI connector
set the SCSI ID.  Putting a shorting block on the first pair of pins
sets the low bit in the SCSI ID, etc.  I don't know that the other three
pairs of pins control.

--
Gordon Davisson
Westwind Computing	(206) 632-8141
4518 University Way NE, Suite 313, Seattle WA 98105