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From: bane@parcvax.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: BMS-100, Adaptek 4000, Quantum 540 "feature"
Message-ID: <340@parcvax.Xerox.COM>
Date: Mon, 1-Jun-87 14:27:28 EDT
Article-I.D.: parcvax.340
Posted: Mon Jun  1 14:27:28 1987
Date-Received: Thu, 4-Jun-87 04:50:20 EDT
References: <329@parcvax.Xerox.COM> <942@sputnik.COM>
Organization: Xerox PARC
Lines: 29
Keywords: Interference, shielding
Summary: Grounding shield makes no difference...

> %	DDDDDDDDDDDDDD	<- Quantum Q540 drive
> %	DDDDDDDDDDDDDD
> %	D            D
> %	--------------	<- Shielding (clad PC board or metal plate works fine)
> %Nylon->S            S
> %stand- AAAAAAAAAAAAAA	<- Adaptek 4000 controller
> %offs ->S            S
> %	BBBBBBBBBBBBBB	<- BMS 100 interface board
> %
> For the shield to be effective, it needs to be electrically connected
> somewhere.  Was it connected to the disk drive (thru mounting screws?)?

I just took a couple of pieces of copper-clad PC board, drilled holes in them,
and put them between the stand-offs for the Adaptek and the metal rails coming
down from the Q540. The copper faces away from the Q540, so it isn't connected
to anything.

	The way I understand it from the BMS folk is that the problem must be
mostly magnetic, since the shield works whether grounded or not.

	As long as the posting system is forcing me to, I'd like to compliment
whoever decreed that included text must be shorter than new text, and suggest
that they relax this restriction for messages shorter than, say, two screens,
to keep people like me from having to add ridiculous "fillers" to messages that
happen to have 10 lines of included text and 8 lines of reply. Sheesh!
-- 
	Rene P.S. Bane
	bane.pa@xerox.ARPA
	...!parcvax!bane.UUCP