[sebhc] H89 BOOT SUCCESS

Barry Watzman Watzman at neo.rr.com
Thu May 17 08:54:47 CDT 2007

The power supplies in all Zenith products prior to the Z-100 series were
linear power supplies, while the power supplies in all PCs are switching
power supplies.  There is no issue with a linear supply being "open" vs. in
a metal box.  In fact, the reason for the metal box is that switching power
supplies have lethal voltages in them, while linear power supplies do not
(except on the primary side of the main power transformer).

The comments about head wear MAY be relevant, but the comments about power
supplies are not relevant.

-----Original Message-----
From: sebhc-bounces at sebhc.org [mailto:sebhc-bounces at sebhc.org] On Behalf Of
Paul A. Pennington
Sent: Thursday, May 17, 2007 9:10 AM
To: sebhc at sebhc.org
Subject: Re: [sebhc] H89 BOOT SUCCESS

    Carroll wrote:

> Is there any way I can check the head alignment?

    In my experience, head alignment problems are rare.  With old drives, 
the problem is usually head wear.  The output level from the heads drops 
below the noise level inside the computer, and they stop working no matter 
what you do to the alignment.  I saw that a lot with Heath/Zenith and Kaypro

computers, with their open power supplies.  Stick the same drive in a PC 
with the power supply in a metal box, and it usually works fine.

    Paul Pennington
    Augusta, Georgia

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