Checking Floppy Drives WITHOUT a Boot Disk
Ira
out that the disk drives do not work AFTER getting diskettes.
Does anyone know how to get as good a gauge as to whether the floppy
drive works or not, short of having a boot disk? This applies to Model
I and III/4.
Thanks!
Knut
>
>> Thanks!
>
> Barry
> =====
> Home page
> http://members.iinet.net.au/~barry.og
Hi
I guess one could do some "i/o" with ROM basic to check that some of the hardware works... Machine
Language disk i/o & other mysteries explains pretty much how the interface works and also has small
programs for doing reading. Possibly one could put such a program on "tape" and distribute a cas
file. I.e. a selfcontained program that does not need s DOS that can read sectors off a disk.
Something like DOSPLUS' DISKZAP would be nice.
Sometime the drive is mechanically bad and might destroy any media even if all the electronics
works, for example an SS drive where someone has used a DS type disk cleaner "diskette".
I would definitely have a good look through the opening to see that everything is as it should be.
maybe even open it.
I would try to boot without a disk and see what happens (does the head seek to 0, does it spin at
approximatly the coorect speed). One might have to move the head away from 0, and then one might
have to open the drive to do that, for to see that it seeks to 0... Maybe ROM basic can be used to
move the head back and forth.
I'd let it try too boot a disk that is not needed, expendable. For example an old 1.2MB or 360K pc
floppydisk. Then to listen to it and hear that it sound normal.
Knut
N Morrison
There was a catseye disk which read out the drive condition on screen.
Expensive when new - and I saw one once on eBay - mucho bucks.
You can't copy the disk - they're made on special 'wobbling' hardware!
I imagine you could write a program that gave basic information on
similar lines - don't recall ever seeing such a thing.
Mike Y
"N Morrison" <Anoth...@gmail.com> wrote in message
news:b8229659-6728-4240...@b14g2000yqd.googlegroups.com...
At one point there was even a 'bootable' disk that had the cats-eye pattern
on it. You could even do it with 'tricks' and have the cats-eye be readable
data and the program will then let you align from the screen instead of with
an oscilloscope. Tandy sold the disk through their National Parts at one
time.
And you're right, they have to have the 'alignment track' put on with a
'wobble'. And the wobble has to be 'set' against the index pulse. (Well,
on the scope version)
But you can do an alignment without the cats-eye, if you're careful. If
you have a KNOWN good diskette, you can just 'center' the track. Set
up a program to read all the sequential sectors on a track and throw the
data away. Take the drive out of alignment slowly in one direction until
it fails. Then return and go out of alignment the other direction. Do this
a number of time and then set the alignment to the midpoint between the
two failures. You'll be fairly close. Not as good as a cats-eye, but
usually close enough.
Ira
people asking me for boot disks (which I prepare from my dwindling
supply of 5.25" disks and mail off; at my cost) only to hear that
their drive doesn't work.
Since I would just as soon NOT waste the disks or the postage on
systems with bad drives, I was wondering if there were OUT commands to
spin the drive up, for example ... basically to do what is possible
with the person having NO floppy disks.
Thanks
On Thu, 2 Jul 2009 18:47:42 -0400, "Mike Y" <j...@user.com> wrotf:
Mike Y
simple commands. (It would be tough to keep up with the read or write
though).
Just to see if the drive starts you should be able to select the drive. You
should also be able to seek and check for home with simple commands.
I'd have to go get a book to figure out how to do it, but it's not hard to
do. Depending on how extensive you want to test, you could do a simple
program that you type in.
"Ira" <youknowwhe...@nospam.com> wrote in message
news:esgq459id6ggnrb51...@4ax.com...
Matthew Reed
> My 'problem' is more everyone elses problem. I have seen a spate of
> people asking me for boot disks (which I prepare from my dwindling
> supply of 5.25" disks and mail off; at my cost) only to hear that
> their drive doesn't work.
>
> Since I would just as soon NOT waste the disks or the postage on
> systems with bad drives, I was wondering if there were OUT commands to
> spin the drive up, for example ... basically to do what is possible
> with the person having NO floppy disks.
On the Model I in Level II BASIC:
POKE 14304,1 should turn on drive 0
POKE 14304,2 should turn on drive 1
On a Model III or 4 in Level II BASIC:
OUT 244,1 should turn on drive 0
OUT 244,2 should turn on drive 1
Those commands should at least tell if the floppy drives can still spin.
--
Matthew Reed
http://www.trs-80.org
http://www.trs-80emulators.com
Ira
instructions. If there are any other tests (such as stepping the
head), I would love to know those as well (I figure that if the drive
spins up, and the head steps, that's good enough).
On Fri, 03 Jul 2009 10:17:21 -0500, Matthew Reed <m...@trs-80.org>
wrotf:
Herbert Johnson
> Thanks! I have updated the diskette request page to include these
> instructions. If there are any other tests (such as stepping the
> head), I would love to know those as well (I figure that if the drive
> spins up, and the head steps, that's good enough).
>
I have some technical Web pages about floppy drives and diskettes,
http://www.retrotechnology.com/herbs_stuff/drive.html
and I'm active in the CP/M discussions in comp.os.cpm. Also I do
repair 8-inch and some 5.25 inch drives, and work with some old 3.5-
inch drives from Apple Macs. My experiences and impressions is that
many non-working drives get dirty and gummy; then the heads are dirty.
Cleaning and lubrication fixes some of that, but even so some drives
have mechanical or electronic faults, or for some reason the "heads"
are "misaligned". So even a fully operational drive which can read and
write diskettes, if mis-aligned can't read or write to some other
drive. (Beyond that, of course, floppy drive controllers or systems
can have their own problems.)
So for most systems, and for nontechnical users, a "boot diskette"
*for that system* is kind of the acid test. In and around the CP/M
world, we look to Dave Dunfield's "imagedisk" program and sets of
imaged boot diskettes. His programs let a PC compatible create the
images which he archives. Then, users download the images to create
them locally on a PC with the correct drive. (Dave's site discusses
these issues at length, read the site to answer questions.)
http://www.classiccmp.org/dunfield/img/index.htm
Herb Johnson
retrotechnology.com
N Morrison
> My 'problem' is more everyone elses problem. I have seen a spate of
> people asking me for boot disks (which I prepare from my dwindling
> supply of 5.25" disks and mail off; at my cost) only to hear that
> their drive doesn't work.
>
> Since I would just as soon NOT waste the disks or the postage on
> systems with bad drives, I was wondering if there were OUT commands to
> spin the drive up, for example ... basically to do what is possible
> with the person having NO floppy disks.
'Trakcess' is a program which accessed and manipulated the drive,
mostly in Basic but with some M/L software.
A read through of the code might give some hints as to what Basic can
do.
Neil
Mark Whitlock
Since PC drives are more plentiful, you may want to suggest they
buy one and a catweasel card. If they bulk at this, they are most
likely not willing to put forth any real effort, and are just wasting
your time. Yes, I have mailed off dozens of boot disks to people in
the past, mostly for the T2000. At least have the people send you the
disks and a SASE. Personally I never did, but my volume was only
several sets a year.
Slight cynical,
Mark Whitlock
P.S.
Thank you for running the web site for so many years.
Ira
Many people who contact me cannot afford the floppy drive or the
catweasel (catweasels, while wonderful, are VERY expensive, and the
people probably aren't going to do bulk). I also wouldn't ask for the
disk to be sent with a SASE for a few reasons ...
1) Most people don't have blank 5.25" non-HD disks;
2) Some brands (CDC, for one) are simply awful and did not withstand
the test of time at all. Many disks just won't hold a write. Making
people send me their disks would just increase their cost. Right now
I am still doing OK on inventory (people who send me their disks to
read tend to not want them back; and those become the disks I use to
make DOS disks for others).
3) People who need boot disks tend to not have the slightest idea what
they need (e.g., people with 4P's asking for only the hacked 4P
NewDos/80 instead of regular M4 disks; and people with M4's not asking
for M3 disks [no matter how many times on the web page I try to point
that out]. Bottom line is that they probably wouldn't send the right
number of blanks anway :)
4) Many people who ask live in other countries. The postage is CRAZY,
and customs applies ... no need to do that TWICE
... but most of all ..
5) I don't mind doing it for those in need. The risk of sending the
disks and spending the postage is a small price to pay to help people
out here, so I don't mind doing it. That said, if we knew that the
disks would be of no benefit to them because their system does not
work - THAT would be a good time to put on the brakes :)
Thanks!
Ira
On Sun, 5 Jul 2009 13:55:11 -0700 (PDT), Mark Whitlock
<ma...@leadmon.net> wrotf:
Frank Traut
I'm one of the guys that was having problems with my aux
drive. Boot drive works perfect however. Cleaned & lubricated
what I could (would never use a commercial drive head cleaner)
& adjusted the tiny speed pot using a strobe, but still having
problems. Someone hinted that we have drives that are destroying
data. I wonder if that is the case with most of the disks you
sent me. I've got a couple of boxes of NOS Syncom Platinum DS/DD
5-1/4" disks sitting over here from a recent purchase that I'd be
happy to send you, along with your other disks back to re-copy
what it is you sent, but I'm afraid there's more going on
with my drive. After tinkering with the speed, I can get it
to read most of the disks Ira sent, but some are now rendered
"unreadable". And if the drive and computer sits for any
length of time, seems I need to readjust it in order to get
the few remaining disks or their programs to load.
Perhaps I could send my bad drive out to Herb for a going over?
It's not just that some of us can't "afford" this stuff, moreso...
don't want to invest much in what can and probably is going to
end up being flaky hardware. I'd rather use original hardware
anyway than a Catweasel type scenario.
Thanks to all and especially Ira (I did make a donation to
cover the costs of s/h and a little something extra btw).
I'm certainly not here to waste anyone's time and appreciate
the help, advice and goods as I re-learn how to use this cool
platform.
-Frank
Herbert Johnson
> Hi All, especially Ira!
>
> I'm one of the guys that was having problems with my aux
> drive. Boot drive works perfect however. Cleaned & lubricated
> what I could (would never use a commercial drive head cleaner)
> & adjusted the tiny speed pot using a strobe, but still having
> problems. Someone hinted that we have drives that are destroying
> data. I wonder if that is the case with most of the disks you
> sent me. I've got a couple of boxes of NOS Syncom Platinum DS/DD
> 5-1/4" disks sitting over here from a recent purchase that I'd be
> happy to send you, along with your other disks back to re-copy
> what it is you sent, but I'm afraid there's more going on
> with my drive. After tinkering with the speed, I can get it
> to read most of the disks Ira sent, but some are now rendered
> "unreadable". And if the drive and computer sits for any
> length of time, seems I need to readjust it in order to get
> the few remaining disks or their programs to load.
>
> Perhaps I could send my bad drive out to Herb for a going over?
> It's not just that some of us can't "afford" this stuff, moreso...
> don't want to invest much in what can and probably is going to
> end up being flaky hardware. I'd rather use original hardware
> anyway than a Catweasel type scenario.
I don't pretend to know Tandy equipment, so others with experience can
inform you about whether one model or another tends to be more "flaky
hardware". The simple facts are, that computers from the 1970's and
80's are well past their use and design lifetimes. They have
components which degrade or fail with age, use, and environment. They
often need more than adjustment, they need component-level repair.
That does not make them "flaky" and a "poor investment" - just raises
the stakes. But I don't anticipate, that computers of the 21st
century, will either last OR be repairable in 30 years. I do
anticipate that many 70's computers WILL BE, 30 more years out.
Diskettes will fail over time as the surface coatings become brittle;
some brands degrade more than others; also mold and prior storage
conditions are factors.
But a diskette in a drive can be damaged, if the head of the drive has
junk on it - it can scrape off brittle coatings. So examine the
surface of your diskettes closely, before and AFTER use, on your
drives - learn what damage looks like. Even good drives can't read
disks if the head gap is clogged, even just a tiny tiny bit, with iron
oxide. Read about "head gap" "read/write heads" if you search for more
information, but you've got to clean those heads. I use a Q-tip and
alcohol.
It's informative that you have a system with one good-working drive
and one drive which tends to fail. That suggests the problem is with
the drive, not the rest of the system. Swap the drives (if you can) to
confirm this, to see if the problem "stays" with the drive.
I don't quite buy that you can change drive rotation speed and it
"fixes" it but only for a while. If a drive can't hold rotation speed,
it has problems, period. If something else is going on, damaging your
disks, that's bad news. Seems to me, under all your circumstances,
*find another drive* to replace the undependable drive. If you find
you have a number of drives which "fail", then check your methods. If
only that one drive failed, you've contained the damage.
Nothing worse than a drive that fails *occasionally*. Who wants to
write a diskette with such a drive? As for "sending it to Herb", I
don't quote prices in an Internet Usenet newsgroup. But I think it's
likely the cost of shipping a drive back and forth, plus any cost for
time spent by most anyone who charges for time; all that will be MORE
than just buying a drive from someone and receiving that drive. Best
is a drive from a matching system, but at the least a drive of the
same brand and model. Past that, you have to know "stuff" to use other
kinds of drives.
This is very generic advice, but I'm not giving Tandy-centric advice.
Hope it's useful. Don't blame me if "my advice causes you" to break
anything. But anything I have to say at any length, is on my Web site.
Mostly, I carry good information from other people.
Herb Johnson
retrotechnology.com
Frank Traut
> I don't pretend to know Tandy equipment, so others with experience can
> inform you about whether one model or another tends to be more "flaky
> hardware". The simple facts are, that computers from the 1970's and
> 80's are well past their use and design lifetimes. They have
> components which degrade or fail with age, use, and environment. They
> often need more than adjustment, they need component-level repair.
> That does not make them "flaky" and a "poor investment" - just raises
> the stakes.
Don't get me wrong... I fully understand what's at stake here. My
definition of "flaky" applies to the gamble of dealing with any and
all vintage electronics: typical scenario is if I was to send this out
to be repaired, sure... a component may have been found to be out of
tolerance and it gets replaced. But down the road, maybe some other
component needs replacing sooner than later. Spending hundreds of
dollars in time, parts and shipping to and fro doesn't make any sense.
Finding a replacement drive for XX amount of dollars and gambling
something will go wrong (or not) any time soon does make sense. Reason
I would consider sending it out to be looked at is:
a) from your e-mail, seemed that you offered this service
b) am not one to simply or quickly throw things in the garbage bin
c) the few responses I got that offered to sell me a replacement
drive from my original thread have all flaked out! lol Yeah, they
disappeared off the face of the earth and do not reply to e-mails
anymore. VERY common netiquette in this day and age I must say.
Thanks for the help Herb. I restore vintage coin-op arcade, audio gear
Commodore and Atari computer equipment and am familiar with most of
the common sense advice here. If I don't get any serious bites to set
me up with a replacement drive, may I PM you and get a quote? It's
likely I'll bide my time and land one here before too long and then I
guess I'll just keep the old drive for spare parts.
Oh - and yes, the problem may not be entirely be speed centric, but
it does seem a little more than sheer coincidence that varying the
rotation speed DOES improve reads. This might also indicate a bad or
worn belt. When I have a block of time to fiddle around again, guess
I could always swap belts too and see if the problem migrates.
-Frank
Frank Traut
> a) from your e-mail, seemed that you offered this service
^^^^^^^^^^^^^^^^
Whoops! Sorry, meant to exclaim "from your posting"...
tur...@gmail.com
Matthew,
That's a bit of nice small code to get the drives spinning.
Is there an additional short snippet of a few lines that can be run to
somehow detect the index hole sensor?
I think TRAKCESS was all written in BASIC but I don't know if it was
hybrid code (i.e. with assembler calls)...
I would think that even with HD diskettes at least seeing the index
hole sensor pulsing would indicate that the drive was working pretty
well...
... but then again, the most likely failure of these drives isn't
going to be a belt problem but more likely dirty heads (-?)
Mike Y
----- Original Message -----
From: "Herbert Johnson" <herbrj...@gmail.com>
Newsgroups: comp.sys.tandy
Sent: Monday, July 06, 2009 7:24 PM
Subject: Re: Checking Floppy Drives WITHOUT a Boot Disk
>But a diskette in a drive can be damaged, if the head of the drive has
>junk on it - it can scrape off brittle coatings. So examine the
>surface of your diskettes closely, before and AFTER use, on your
>drives - learn what damage looks like. Even good drives can't read
>disks if the head gap is clogged, even just a tiny tiny bit, with iron
>oxide. Read about "head gap" "read/write heads" if you search for more
>>information, but you've got to clean those heads. I use a Q-tip and
>alcohol.
>
>Herb Johnson
>retrotechnology.com
The motor speed may be a simple fix, but don't count on it. There was also
a problem in that some of the early drives, like the Shugart, had a 'DC
balanced' amplifier on the front end for the read head, and as such, had to
be adjusted so that pulses were symetrical for flux changes. Later drives
had an AC coupled amplifier and no adjustment was necessary.
One thing to warn you about though is the 'head load pad'. This is the
little fiber pad that pressed on the diskette and caused the media to deform
properly across the head. If they picked up particulate matter (and they
did a LOT!) they could score a diskette. What makes them really bad is that
if a diskette is scored and there is a 'hard spot' in the pad the diskette
will deform slightly the WRONG way over the head and not be read. Or
worse, it can physically damage a diskette. A hard spot on the pad can
cause material to build up on the head in a coresponding spot. While that
wasn't as bad in the 5.25" drives as it was in the 8" Model II's (I've seen
Model II diskettes that you could SEE through in a ring from the drive
spinning all day long on one track!) it could still cause problems.
I always cleaned my heads with a Q-Tip and denatured alcohol. Don't use
rubbing alcohol as it has too much water in it. And make sure the head is
clean and dry before you let the arm back. Do NOT let the load arm 'snap
down' against the head after you've cleaned it. Finally, I always used an
X-Acto knife on the pad. No, not to 'cut' anything, but to 'pet' it like
you would do to a cat with your hand, keeping the blade at a small angle to
the surface and taking it BACKWARDs across the fiber, not so that it could
cut anything, but to dislodge any particulate matter and to 'fluff up' the
pad a bit. Then I'd put in a diskette rotated so that the window was NOT
over the head, lower the arm, and PRESS it gently to 'pack' the fiber
slightly.
Replacement pads used to be available (I think about 15 cents) and were easy
to snap out and replace, but I think anything like that are long gone as
replacement parts. Oh, I should say, make sure you even HAVE a pad! I've
seen drives where the pad has fallen out! If that happens, go to a hobby
shop and get some of those felt pad to glue onto the bottom of metal box.
Then go to a stationary store and get a 'punch' (looks like pliers) a bit
bigger then 1/8". Punch out a pad, and stick it in there. If you can't get
a punch, go to WalMart and buy a 'leather punch'. Looks like a big pair of
pliers with a 'star' wheel on the end with all different sizes of holes.
Mike Yetsko
Herbert Johnson
> The motor speed may be a simple fix, but don't count on it....
> One thing to warn you about though is the 'head load pad'....
> I always cleaned my heads with a Q-Tip and denatured alcohol....
>
> Mike Yetsko
This is good information, I'd like to add it to my Web pages on floppy
drives. Mike, please contact me privately via my Web site at
retrotechnology.com, I like to get permission to quote you, a Web link
to you if you are on the Web. Thanks!
Herb Johnson
Mike Y
"Herbert Johnson" <herbrj...@gmail.com> wrote in message
news:1078950c-f108-454c...@d4g2000vbm.googlegroups.com...
Hi Herb!
Just spotted your post this morning. I'll send you an email.
Mike