From: davisson@stein.u.washington.edu (Gordon Davisson)
Subject: Re: Interesting ADB behaviour on C650
Organization: University of Washington, Seattle
Lines: 34
NNTP-Posting-Host: stein.u.washington.edu

In article <1993Apr16.091202.15500@waikato.ac.nz> ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) writes:
>In article <1993Apr15.181440.15490@waikato.ac.nz>, I said:
>> I know that plugging and unplugging ADB devices with the power on is "not
>> supported", and you can hit problems if you have multiple devices with
>> clashing addresses, and all that.

>I've had a couple of e-mail responses from people who seem to believe that
>this sort of thing is not only unsupported, it is downright dangerous.
>
>I have heard of no such warnings from anybody at Apple. Just to be sure, I
>asked a couple of our technicians, one of whom has been servicing Macs for
>years. There is *no* danger of damaging logic boards by plugging and unplugging
>ADB devices with the power on.

Noooooooo!  I've been servicing Macs for years too, and I've had to
repair a number of motherboards that had been damaged this way.  It's
rare, but it does happen.

Mind you, this doesn't mean you shouldn't do it.  The parts that can
blow (the ADB power fuse and RF filter) aren't too expensive, so IF you
have a someone around who can do component-level repair, it may be worth
the risk (especially if you're around Seattle, 'cause you might get to
pay *me* to fix it :-))..  On the other hand, if your only repair option
is the Apple-standard logic board swap (major $$$$), you should probably
play it safe.

>SCSI, yes, ADB, no...

SCSI: yes, ADB: yes, Floppies: yes...  They can all cause trouble.

--
Gordon Davisson		davisson@stein.u.washington.edu
Westwind Computing	(206) 632-8141
4518 University Way NE, Suite 311, Seattle WA 98105
