[comp.sys.mac.hardware] Mac+ Internal HD

osborn@ux1.lbl.gov (James R Osborn) (05/16/91)

I *AM* going to install a Quantum LPS-52 SCSI drive
inside my Mac+.  The drive says 6 watts.  It is a low
profile, low power consumption drive.  My question is
do I really have to spend $50 for a seperate 20 watt
power supply for the drive?

Or if I upgrade my Mac+ power supply (install new various
components as per Larry Pina's "Macintosh Repair Secrets..."
suggestions), and adjust the voltages with the drive
installed, will *THIS* work?

Just what are the Mac+'s power supply ratings?  Someone
told me that if I install a drive like this, there is a
significant drain particularly on startup.  The drain,
so I was told, is enough to possibly cause the drive to
trash itself during startup.  I don't want this!  :^o

What do people think?
-- James

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| James R. Osborn              | It just goes to show you it's always   |
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stanfiel@testeng1.misemi (Chris Stanfield) (05/17/91)

In article <13260@dog.ee.lbl.gov> osborn@ux1.lbl.gov (James R Osborn) writes:
>
>I *AM* going to install a Quantum LPS-52 SCSI drive
>inside my Mac+.  The drive says 6 watts.  It is a low
>profile, low power consumption drive.  My question is
>do I really have to spend $50 for a seperate 20 watt
>power supply for the drive?

The Mac+ supply is flakey - it is a very marginal design. I would
install the extra supply AND A FAN!!! A SCSI drive typically draws >2A
at 12V on startup, but typically uses only 0.5A at 12V when running.
The 5V drain is ~0.5A, so your low poer unit probably does all it
says, but it still may draw a lot of power on power-up, and the Mac
supply can't supply it. I suggest you test the drive - it doesn't hurt
to just power them up with nothing else connected, but have the
terminating resistors in.

Have fun!

Chris Stanfield, Mitel Corporation: E-mail to:- uunet!mitel!testeng1!stanfiel
(613) 592 2122 Ext.4960
We do not inherit the world from our parents - we borrow it from our children.