colin@vu-vlsi.UUCP (Colin Kelley) (06/07/86)
We've got several PClones around here, all about 3 years old. The floppy
drives are rapidly degrading in performance. That is, lots of MS-DOS
complaints about "Bad disk" and "Can't find sector" and all that...I adjusted
the data separator pots to specs from the clone manufacturer (Corona), but
this hasn't help. So now I'm suspecting some adjustment on the drive itself.
I assume the drives have alignment and speed adjustments, right? Does someone
know how to do this, or know where I can get order a reasonably inexpensive
manual to describe such adjustments? Some of the drives are MPI copies of
the old original PC full-height Tandom TM100-2s, and some of the drives are
new 1/2-height Teacs...
Thanks for any info!
-Colin Kelley ..{cbmvax,pyrnj,psuvax1}!vu-vlsi!colin
+++
ATHkpk@gitpyr.UUCP (Kevin P. Kleinfelter) (06/09/86)
In article <336@vu-vlsi.UUCP>, colin@vu-vlsi.UUCP (Colin Kelley) writes: > We've got several PClones around here, all about 3 years old. The floppy > drives are rapidly degrading in performance. That is, lots of MS-DOS > complaints about "Bad disk" and "Can't find sector" and all that...I adjusted > the data separator pots to specs from the clone manufacturer (Corona), but > this hasn't help. So now I'm suspecting some adjustment on the drive itself. > I assume the drives have alignment and speed adjustments, right? Does someone > know how to do this, or know where I can get order a reasonably inexpensive Speed adjustment is easy. Remove the drive, reconnect the cables (or leave them connected). On the bottom of the drive (or the top, depending on your point of view) you will see a large pulley with black marks on it. Shine a fluorescent light on this pulley, and make the drive motor run (perhaps by booting or DIR on the removed drive). You should notice the lines seem to stand still under the fluorescent light (like the strobe adjustment on expensive record players). If the lines seem to move, find a multi-turn trimmer pot on the controller card, and adjust it a little, and check again. Adjusting head alignment is a royal pain. Pay someone to do it. Finally, try cleaning the heads. A little alchohol on a Q-tip is nice, but if you prefer to spend $$, you could buy a head cleaning diskette (i prefer the wet cleaning disks instead of the dry cleaning disks, but this is just personal preference).
pmg@aplvax.UUCP (P. Michael Guba) (06/10/86)
In article <1860@gitpyr.UUCP> kpk@gitpyr.UUCP (Kevin P. Kleinfelter) writes: | In article <336@vu-vlsi.UUCP>, colin@vu-vlsi.UUCP (Colin Kelley) writes: | > We've got several PClones around here, all about 3 years old. The floppy | > drives are rapidly degrading in performance. | | Finally, try cleaning the heads. A little alchohol on a Q-tip is nice, FYI in net.audio I once read that Q-tip brand cotton swabs should not be used for cleaning heads because they contain a small amount of paraffin to help them keep their shape. The paraffin leaves a residue on the heads that attracts dirt. That posting recommended using cotton swabs sold for more pure medical or audio use. Also, swabs sold for cleaning digital tape drives can normally be found around a computer center. Just thought you'd like to know, Mike -- P. Michael Guba ...seismo!umcp-cs!aplvax!pmg JHU/Applied Physics Lab Johns Hopkins Road Laurel, Maryland 20707 (301) 953-6829
russack@ucsfcgl.UUCP (Joe Russack%CGL) (06/10/86)
> >Finally, try cleaning the heads. A little alchohol on a Q-tip is nice, >but if you prefer to spend $$, you could buy a head cleaning diskette (i >prefer the wet cleaning disks instead of the dry cleaning disks, but this >is just personal preference). wouldn't use alchohol on the heads- it leaves a residue, and a residue on your heads is the classic definition of no fun. Use something that won't leave a residue of any sort (I believe ammonia won't, but I am not sure). Also: a Q-tip s not a great idea, either. A cotton swab (medical quality) would be better- it tends to have fewer abrasive fibres in it. Be NICE to your heads.... Joseph Russack. uucp: ucbvax!ucsfcgl!russack
bright@dataioDataio.UUCP (Walter Bright) (06/12/86)
In article <9879@ucsfcgl.ucsfcgl.UUCP> russack@ucsfcgl.UUCP (Joe Russack%CGL) writes: > wouldn't use alchohol on the heads- it leaves a residue, and a residue > on your heads is the classic definition of no fun. Use something that > won't leave a residue of any sort (I believe ammonia won't, but I am > not sure). Also: a Q-tip s >not a great idea, either. A cotton swab (medical quality) would be better- it >tends to have fewer abrasive fibres in it. Rubbing alcohol leaves a residue, as it is only about 70% alcohol and has additives. Use denatured alcohol, which is about 97% or 98% pure, and evaporates cleanly. Denatured alcohol is available at most drugstores. Denatured alcohol is essentially pure alcohol with a small amount of poison added in order to make it undrinkable (to escape the liquor tax). Laboratory alcohol is 98% pure (2% water). It is apparently impossible to eliminate that last 2% of water. Any chemists out there care to explain why?
rde@ukc.UUCP (06/13/86)
About speed adjustment. The IBM service manuals seem to indicate you
should use the strobe lines on the drive only for rough adjustment (so
you can get the drive working enough to load a proper program for the
job). The IBM advanced diagnostics contain a program which will let you
twiddle the speed adjustment and see the speed changes expressed as
numbers.
I have a program which I *think* is PD; it shows a scale on the screen
and a pointer indicating the speed. Anyone interested in a posting once
I have checked?
--
Bob Eager
rde@ukc.UUCP
rde@ukc
...!mcvax!ukc!rde
Phone: +44 227 66822 ext 7589kaufman@Shasta.UUCP (06/14/86)
In article <1017@dataioDataio.UUCP> bright@dataio.UUCP (Walter Bright writes: > >Laboratory alcohol is 98% pure (2% water). It is apparently impossible >to eliminate that last 2% of water. Any chemists out there care to >explain why? I think the correct ratio is 95% alcohol (190 proof) to 5% water. At that point the partial pressures of alcohol vapor and water vapor are such that further distillation does not change the ratio. You can get rid of the last water by adding sulphuric acid... should leave the heads bright and clean too!
dpz@topaz.RUTGERS.EDU (David P. Zimmerman) (06/16/86)
> I have a program which I *think* is PD; it shows a scale on the screen > and a pointer indicating the speed. Anyone interested in a posting once > I have checked? Go for it! It's a good utility I've been looking for for a while.... Davidann -- Name: David P. Zimmerman Nickname: "Davidann" (don't ask) Cute quote: " (well, *I* think it's cute!) Arpa: DZIMMERMAN@BLUE.RUTGERS.EDU Uucp: ...{allegra, harvard, seismo, sri-iu, ut-sally}!topaz!dpz
dan@rna.UUCP (Dan Ts'o) (06/16/86)
In article <1017@dataioDataio.UUCP> bright@dataio.UUCP (Walter Bright writes: >Rubbing alcohol leaves a residue, as it is only about 70% alcohol and has >additives. Use denatured alcohol, which is about 97% or 98% pure, and >evaporates cleanly. Denatured alcohol is available at most drugstores. > >Denatured alcohol is essentially pure alcohol with a small amount of >poison added in order to make it undrinkable (to escape the liquor tax). > >Laboratory alcohol is 98% pure (2% water). It is apparently impossible >to eliminate that last 2% of water. Any chemists out there care to >explain why? Rubbing alcohol is 70% ISOPROPYL alcohol, the type of alcohol most recommended for cleaning computer peripherals. True, most drug store formulations include additives like perfume, thus it would be better to get more pure isopropyl. Drinking alcohol is ETHANOL (200proof == 100%). It certainly is possible (and commercially available) to get 100% ethanol. However left in contact with the atmosphere, 100% ethanol quickly absorbs water from the air. Also, lab 100% ethanol often has trace amounts of benzene (used in the distillation process), thus it is not wise to use this stuff in party punch (although many lab parties do). Needless to say, there are many other types of alcohols...
jeffd@ittvax.ATC.ITT.UUCP (Jeff Denenberg) (06/16/86)
> > About speed adjustment. The IBM service manuals seem to indicate you > should use the strobe lines on the drive only for rough adjustment (so > you can get the drive working enough to load a proper program for the > job). The IBM advanced diagnostics contain a program which will let you > twiddle the speed adjustment and see the speed changes expressed as > numbers. > > I have a program which I *think* is PD; it shows a scale on the screen > and a pointer indicating the speed. Anyone interested in a posting once > I have checked? > -- > Bob Eager > > rde@ukc.UUCP > rde@ukc > ...!mcvax!ukc!rde > > Phone: +44 227 66822 ext 7589 The program COPYIIPC has a /T option which does a good job of continuously testing a floppy's speed. It is not public domain but is well worth the discounted price of ~$20.
henry@utzoo.UUCP (Henry Spencer) (06/17/86)
> Laboratory alcohol is 98% pure (2% water). It is apparently impossible > to eliminate that last 2% of water. Any chemists out there care to > explain why? Not impossible, just somewhat expensive. Also somewhat silly for most purposes, since the alcohol will promptly get it back by absorbing water vapor out of the air. Since it's fairly easy to get that last little bit (I'm not sure 2% is right, I think it's rather more) out as needed for the few situations where even traces of water are unacceptable, it's not worth trying to supply it 100% pure. -- Usenet(n): AT&T scheme to earn revenue from otherwise-unused Henry Spencer @ U of Toronto Zoology late-night phone capacity. {allegra,ihnp4,decvax,pyramid}!utzoo!henry
andrew@stc.co.uk (06/18/86)
In article <502@rna.UUCP> dan@rna.UUCP (Dan Ts'o) writes: | Drinking alcohol is ETHANOL (200proof == 100%).... Actually 100proof spirit (at least originally --- I don't know what your legistators have done :-)) is more like 56% alcohol (+/- 2% I'm not THAT sure without looking it up). The funny figure came from the excise-man's `proof' that he was dealing with spirit by wetting black powder and lighting it. As for excisemen --- I'm sure transmitting my opinions of excise and it's enforcers is illeagal... -- Regards, Andrew Macpherson. <andrew@tcom.stc.co.uk> {inset,ist,root44,stl,ukc}!stc!andrew -- Violence is the last refuge of the incompetent -- Salvor Hardin `Foundation:Isaac Asimov'
srp@ethz.UUCP (Scott Presnell) (06/18/86)
[ munch, munch... In article <1017@dataioDataio.UUCP> bright@dataio.UUCP (Walter Bright writes: >Laboratory alcohol is 98% pure (2% water). It is apparently impossible >to eliminate that last 2% of water. Any chemists out there care to >explain why? Well, Distsilled EtOH *is* 100%, as long as your careful and use oven dried glassware. But for what your talking about, its just that EtOH is just too hydroscopic to give up the water (likes water too much). If you can find it, isopropanol, 2-Propanol, or isopropyl alcohol (all the same stuff but different names), is really the stuff to use for this. I use it on my tape deck heads. DONOT use ammonia or any other caustic substance, it will start eating at the metal. #include <disclamers.h> -- ----------- Scott Presnell Eidgnoessische Technische Hochschule, Zuerich (ETH-Zentrum) Labor Fuer Organische Chemie Universitaetsstrasse 16 CH-8092 Zuerich Switzerland. uucp: ...seismo!mcvax!cernvax!ethz!srp (srp@ethz.uucp) earn/bitnet: Benner@CZHETH5A