Path: utzoo!attcan!uunet!husc6!mailrus!ames!pasteur!agate!ucbvax!RADC-TOPS20.ARPA!GUBBINS
From: GUBBINS@RADC-TOPS20.ARPA (Gern)
Newsgroups: comp.sys.zenith.z100
Subject: Re: Z100 disk drive problem, Please Help
Message-ID: <12448373370.8.GUBBINS@RADC-TOPS20.ARPA>
Date: 21 Nov 88 18:37:14 GMT
References: <857@speedy.mcnc.org>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 11

If the A: drive is okay, then the controller is fine and the drive
is probably out of alignment.   If you replaced the timming PLL or
4 phase clock chip on the controller, the timming trim pots may need
to be tweeked to recalibrate the timming (B: may be more sensistive).
The calibration is detailed in the Z-100 Tech Manual and requires a
'scope, frequency counter, and a voltmeter.  The Heath Kit version
has a calibration board that I have never seen that does it with 
only a voltmeter (so I am told... Info, anyone???).

Gern
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