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From: bernard@prlb23.prlb.philips.be (bernard)
Newsgroups: comp.sys.mac.system,comp.sys.mac.misc
Subject: Quantum internal HD as external HD
Keywords: hard disk, scsi id
Message-ID: <81@prlb23.prlb.philips.be>
Date: 14 Jun 91 08:48:36 GMT
Followup-To: poster
Organization: Philips Research Laboratory Belgium
Lines: 70



I 've bought a new internal CDC hard disk for my old Mac II. Very fast,
silent compared to the `old' (1987) 40Mb Quantum I had. I've also got a
box with alimentation to put my old Quantum in it.  The box has a scsi
id selector terminated by 2 connectors of 3 wires : the first connector
are the common wires and the second carries the "1", "2" and "4" wires
that will generate scsi identification of 0 to 7.

Well, now the problem : where do I connect these wires to my old
Quantum...  The Quantum back side has 2 connectors: a big one which is
the scsi i/o and a small one made of 2 rows of 8 pins. Maybe these are
to be used for scsi id setting ? Can someone send me info on how to use
these pins ?


The back side of my old Quantum 40Mb looks like this:

     _________________________________________________________
     | HD metal box                                          |
     | Q250       76-45004  56                  alim conn.   |
     |                                          	V    |
     |                                                 ||||  |
     =========================================================
              .........................   ........         ^
              .........................   ........      circuit board

		         ^                   ^
		   scsi i/o connector      other connector
					  (scsi id setting ??)


On the circuit board, there is also a row of 2 * 8 pins for jumpers.
There are 2 jumpers put in this row. The row is just below a big squared
IC ( OMTI 20508, NCR-0380296...).  The part of the board around this row
looks like this:

    board
      V
     _______________________________________________
    |     ____________________  _____________       |
    |	 | scsi i/o connector || other conn. |      |
    |     --------------------  -------------       |
    |                                               |
    |                                               |
    |                   ___________                 |
    |                  |           |
    |                  | OMTI      |
    |                  | NCR-...   |  <- big IC
    |                  |           |
    |                  |           |
    |                   -----------
    |
    |     		::::|::|	<- jumpers receiver pins
    |			                   some of them (|) have jumpers
			


What's the use of these jumpers ?

The CDC 3.5 HD is quite silent. So now, the main source of noise in my old
Mac II is the fan. Are there more silent fans i could use ?

Thanks.


Yves Bernard			bernard@prlb.philips.be
Philips Research Lab, Belgium
4 avenue Einstein
1348 Louvain-La-Neuve