Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!husc6!sunfs2!kent
From: kent@sunfs2.camex.uucp (Kent Borg)
Newsgroups: comp.sys.mac
Subject: Re: Can an SE internal hard disk be used in a Plus?
Message-ID: <323@sunfs2.camex.uucp>
Date: 10 Feb 89 16:42:27 GMT
References: <1989Feb1.162245.857@mntgfx.mentor.com> <1470@cooper.cooper.EDU>
Reply-To: kent@sunfs2.UUCP (Kent Borg)
Organization: Camex, Inc., Boston, Mass USA
Lines: 71

In article <1470@cooper.cooper.EDU> joseph@cooper.cooper.EDU (Joe Giannuzzi) writes:
>in article <1989Feb1.162245.857@mntgfx.mentor.com>, tomc.build@mntgfx.mentor.com (Tom Carstensen) says:
>> 
>> Does anyone have any thoughts on using an Apple internal hard
>> disk from an SE in a Mac Plus?  A friend has a SE w/ 20 Meg
>> hard disk and he would like to get a larger drive, and we
>> want to know if it is possible to install the SE's hard disk in a
...
>	I am not certain of this but I think the Mac Plus can't
>	have an internal hard drive because it doesn't have an
>	internal SCSI port.  If the Mac Plus does have an internal
...


The problems are the purely practical ones (which is what engineering
is all about).  

If you want to put the disk inside the Plus you will have to worry
about:

	-Power supply. The disk drive will want clean DC power,
	 probably 5 and 12 volts.  The Plus doesn't have any extra.
	 You will have to add a power supply.
	-Heat.  The disk will produce heat.  The Plus already has
	 plenty of that, you will have to add some sort of fan.
	-Mounting.  You will have to put it some where inside the
	 Plus.  Not too close to the high voltage of the CRT please,
	 not where it will come loose and crash about, etc.
	-SCSI.  You will have to tap into the SCSI lines--there is no
	 connector waiting for you to plug into in there, and you
	 *don't* want to start hand soldering all those lines.
	-Interference.  You will have to be sure there is no mutual
	 electrical interference (conducted or radiated) between
	 everything you add and what is already in there.
	-The result will be a very non-standard contraption that will
	 be very difficult to ever get fixed or sell.

It can be done, it has been done.  It has also been abandoned by those
who did it.  I suspect it is not worth it.  


If you want to put the disk in a separate box and use it as an
external drive your concerns are fewer:

	-Build a box.  Same problems as above, but much fewer.  Should
	 be possible to use standard connectors, standard power supply,
	 standard fan, etc.  Much more physical, electrical, and
	 thermal freedom.
	-Find a box.  If you find one designed just for this purpose
	 (they do exist), it might have everything already in place
	 ready for you to add one disk drive and plug in.  This will
	 cost some money, but is probably worth it.

An external drive has advantages.  Though your Mac is less portable
with an external drive, the drive itself is far more portable.  If you
know anyone else who has a Mac you should consider an external drive.
An external can be daisy-chained for transferring data (not commercial
software please), can be swapped about for diagnostic purposes, can be
hidden in a drawer (on a 6" SCSI cable) for silence.


Third possibility: Sell the drive and buy a new one.  The Apple SE
drive is slow, small, and noisy.  (People blame the fan in the SE for
making so much noise, on a friend of mine's SE it is the Apple disk
drive the sounds like a vacuum cleaner.)

Good Luck.


Kent Borg
kent@lloyd or hscfvax!lloyd!kent or kent%lloyd@hscfvax.harvard.edu