Re: Grounding on the //gs

[Lockar <lockar@nospam.com>]

    I'm sorry guys, that was a typo..  ::: shakes his head at his bad
typing ::  I it should have read: "I went to plug the 3.5 drive in the
unit (smart port, with it off mind you, but it was still plugged in)
and I tapped the sides f both connecters (missed plugging it in, and
the two sides hit each other) and there was a small spark."

   Just to clearfy more, what hit was the sides of the two conectors
for I missed plugging it in, and the sides hit each other.  The I moved
the drive cable to plug it in right, and the spark followed.  Then I
took the cable away to make sure the //gs was really off.  It was off,
and I am well aware of what static can do to computers.  I have had to
replace memory chips in my Apple ][+ in my time because of static.

   It did not do any damage to the drive for I have the drive on
another computer and is working perfectly.  As for the //gs it comes
out and looks for a boot device.  There isn't one because I am afraid
to hook one up.  With out some more input on this.

     Thanks

         -Lockar



In article <20040111162707.01786.00001637@mb-m20.aol.com>, Michael J.
Mahon <mjmahon@aol.com> wrote:

> Lockar wrote:
> 
> >      I noticed today that one of my //gs's might have a grounding
> >issuse.  I'm not sure, maybe you guys let me know what I should be
> >looking for.
> >
> >      I went to plug the a 3.5 drive into the unit (with it off mind
> >you, but still plugged in) and I taped the sides of both contectors (I
> >missed plugging it in, and the two sides hit each other) and there was
> >a small spark.  At first I thought it was stactic (which isn't good, I
> >know.)  But it did it again, so I unplugged it and looks around, but
> >every thing 'seems' find but I don't know.
> >
> >     Is there maybe a grounding wire I'm not seeing. I have replaced
> >//gs mother boards before and I don't remeber there being any grounding
> >wire.
> >
> >   What do you guys think?  Or is this //gs toast? :(
> 
> It must be static, unless you have connected the 3.5" drive to
> something.
> 
> Normally, a 3.5" drive is connected only to an Apple and to
> other drives (daisy chained), so there should be no possibility
> of a ground loop of any sort (which would require that something
> external to the Apple, in the daisy chain, was somehow connected
> to the AC power--but no Apple drive is separately powered).
> 
> The bad news is that unless the shield of the connectors made
> the spark, the discharge may indeed have toasted either the
> interface IC in the drive or the IC in the IIgs, or both.
> 
> The good news is that the connectors are constructed so that
> the shields make contact before any of the signal lines.  But you
> mention putting tape on the "sides"--does this mean that you
> insulated the metal shields?  This is a bad idea!
> 
> Except in the power supply, "grounding" is a relative term.
> What is required is that the "ground reference" of all components
> be the same--that is, metallically interconnected.  Since there
> can easily be a significant difference in potential of unconnected
> components, it is a good idea to bring the components to nearly
> the same potential before completing the metallic connection,
> usually by touching "shield" metal parts of both components
> simultaneously before making the connection (so that your body
> makes a resistive connection between parts of the components that
> can withstand a static discharge).
> 
> -michael
> 
> Check out amazing quality sound for 8-bit Apples on my
> Home page:  http://members.aol.com/MJMahon/