Classic mac fun (and some questions)

[Teo Zenios]

----- Original Message ----- 
From: <trag at io.com>
To: <undisclosed-recipients:>
Sent: Thursday, July 09, 2009 4:05 PM
Subject: Re: Classic mac fun (and some questions)


>>
>     (continued...again...)
> From: "Jeff Walther" <trag at io.com>
> To: cctech at classiccmp.org
> User-Agent: SquirrelMail/1.4.17
> MIME-Version: 1.0
> Content-Type: text/plain;charset=iso-8859-1
> Content-Transfer-Encoding: 8bit
> X-Priority: 3 (Normal)
> Importance: Normal
>
>
>> Date: Thu, 9 Jul 2009 12:00:48 -0400
>> From: Ethan Dicks <ethan.dicks at gmail.com>
>
>> I tried to look that up and found it easy to see that the IIfx needed
>> something odd (I couldn't find specifics), so well done there.  It
>> would be interesting to get the details to see where Apple went off
>> the rails from the SCSI spec.
>
> IIRC, it's a matter of adding a capacitor and maybe a resistor to a
> regular terminator.  There's an Apple Technical Note or similar available
> somewhere.  I probably have a copy squirreled away on my hard drive at
> home.   And I think I remember that they use a somewhat higher value
> capacitor (so add a smaller one in parallel on an existing terminator) and
> a lower resistance (so again, add a resistor in parallel).   But I could
> be misremembering.
>
> Again, IIRC, the IIfx's SCSI was too noise sensitive.  But I've also
> heard/read that that was only true for the early production run and that
> the later built machines did not need the funny terminator.

Neither of my IIfx systems need that terminator to work.