Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!amdahl!dwl10 From: dwl10@uts.amdahl.com (Dave Lowrey) Newsgroups: comp.sys.cbm Subject: Re: Drive alignment test Message-ID: <01sIue74Q91010Je4Sk@amdahl.uts.amdahl.com> Date: 31 Jan 89 14:46:09 GMT References: <10976@s.ms.uky.edu> <24100005@tippy> <849@ttrdf.UUCP> Reply-To: dwl10@amdahl.uts.amdahl.com (Dave Lowrey) Organization: Amdahl Corporation, Houston TX Lines: 45 In article <849@ttrdf.UUCP> carus@ttrdf.UUCP (Bryce W. Carus) writes: >In article <24100005@tippy>, bah@tippy.uucp writes: >> >> This is generally true. If your drive loads a program that is a >> commercial prog. or as you stated, the disk that came with your 1541, >> >> stuff deleted... >> >> your drive is out of alignment, the only sure and accurate way to check >> this is with a digital alignment disk and a dual trace scope. >> >> Bob Hahn tippy!bah@newton.physics.purdue.edu > >...there is a simple way to align a drive with minimum equipment and software. > >The principle behind it is to read the raw AC signal coming off the head and >feed that into a simple filter which rectifies it into a couple volts DC. This >signal can then be read with a simple analog voltmeter. The idea is to use the >output as a "peak" indicator...you are on track when the signal is at it's >peak. You'd want to do this with a decent disk...I use CBM's utility disk. > >This method is fast, accurate, and low cost - junk box parts are all you need. >I've aligned dozens of drives this way for my friends...it works like a charm! > >The test run by the utility disk said I had a good drive but it didn't work >until it was aligned by this method - far superior to the old CSM alignment >program... Sams has a book on repairing the 1541, that describes how to make the probe and what chip to hook it up to. I don't know if they have a book on the 1571...... -- ------------------------------------------------------------------- "This isn't Heaven, this is Cleveland!!!!" Dave Lowrey Amdahl Corp. Houston, Texas (713)-850-8828 ...!{ames,sun,decwrl,uunet,....}!amdahl!dwl10 [ The opinions expressed be those of the author and not necessarily those of his most eminent employer. ]