Xref: utzoo unix-pc.general:3574 comp.sys.att:7316
Path: utzoo!attcan!utgpu!watmath!uunet!portal!cup.portal.com!thad
From: thad@cup.portal.com (Thad P Floryan)
Newsgroups: unix-pc.general,comp.sys.att
Subject: UNIXPC RF shield for hard disk
Message-ID: <21302@cup.portal.com>
Date: 15 Aug 89 04:31:11 GMT
Organization: The Portal System (TM)
Lines: 31

Just received an email from a person who "caught" a reference I made recently
to the RF shield surrounding the hard disk in the UNIXPC.  The person was asking
if his removal of the shield may be contributing to the problems he's having
with his HD.  My answer (names censored to protect the guilty!):
----------
Hi ****!

That shield for the HD is there for a reason!  MOST of the "crap" from the
CRT is directed downwards ... right onto the HD.  It also goes off to the
left (so to speak).

I discovered this with several other computers, too, when attempting to place
either floppies or HDs to the "left" of a monitor ... the "left" or "right"
really depends where the HV flyback circuitry is located in a specific monitor.

In the UNIXPC, operating the internal HD without the RF shield is asking for
possible data corruption; the RF energy beneath the CRT is *VERY* strong; I
discovered this by placing an AM/FM portable radio near the "base" of the CRT
when I had the cover off and the system operating when testing some other
things.

In fact, operating the UNIXPC fully open jams my car radio (AM/FM, "premium
sound", top-of-the-line unit in my T-Bird) at 20 feet; just THINK what that
can do to your hard disk; I had to back my car out of the garage before the
radio would again operate. 

If you can retrieve that shield, do so and re-install it!

Thad

Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]