>
> > The heads are selected by U4 (75451 dual AND gate/driver),
> > the outputs of
> > which are pulled to+5V, and slo drive the bases of Q7 (Head
> 1) and Q6
> > (Head 0), PN2222 transistors via restors. One input of each
> > of the AND
> > gates comes from the power-OK circuit, built round Q9 and Q10
> > (as this is
> > common to both heads, it's working correctly), the other
> > input comes from
> > the sides select signal on the connector (U4b, for head 1) or
> > from that
> > signal inverted by U8b (7414) on U4a, for head 0. That should
> > give you
> > some components to check.
> >
> Are you sure U4a drives Q6 and U4b drives Q7? Tracing the
> board shows them
> on Q7 and Q8. Yikes. Any chance you could scan the schematic
> and email it?
> 1bpp tiff, bmp or pcx would do. The higher the resoultion the
> better, but I
> could probably make due at 150dpi.
>
> You could even send it in seperate parts. I could then stitch
> them together.
> Making some preliminary measurements, it's beginning to look
> like a head
> problem. I am reluctant to actually load the heads until I
> have to. I still
> have not "cleaned" the top head thouroughly, although it seems clean
> examining it through a loop.
>
> I may just install a pair of known good drives in the machine and
> troubleshoot these two independantly. At least I would have
> matching drives
> in the machine until I can figure out what is wrong here.
>
> Thanks,
> Kelly
>
I don't kwow what it means when I reply to my own replies, but here goes. I
have the same continuity measurements on head 0 and head 1. However, if I
swap the controller board (I know, Tony, you generally frown upon "swapping"
for troubleshooting, but I couldn't find anything electrically), the problem
stays with the drive.
So, if I have the same continuity, and the problem doesn't seem to be on the
controller, I can only guess either dirty or magentized heads. I noticed
that if I close the drive with no media and open it slowly, the heads stick
together until there is a bit of load on them to pull apart. Kind of like
the are lightly magnetized.
Since I don't have access to a tape head demagnitizer (hey, all I use is
DTRS for my recording), how else could I demagnetize these heads?
I'm going to bed now. More tomorrow.
Kelly
>
>
> The heads are selected by U4 (75451 dual AND gate/driver),
> the outputs of
> which are pulled to+5V, and slo drive the bases of Q7 (Head 1) and Q6
> (Head 0), PN2222 transistors via restors. One input of each
> of the AND
> gates comes from the power-OK circuit, built round Q9 and Q10
> (as this is
> common to both heads, it's working correctly), the other
> input comes from
> the sides select signal on the connector (U4b, for head 1) or
> from that
> signal inverted by U8b (7414) on U4a, for head 0. That should
> give you
> some components to check.
>
Are you sure U4a drives Q6 and U4b drives Q7? Tracing the board shows them
on Q7 and Q8. Yikes. Any chance you could scan the schematic and email it?
1bpp tiff, bmp or pcx would do. The higher the resoultion the better, but I
could probably make due at 150dpi.
You could even send it in seperate parts. I could then stitch them together.
Making some preliminary measurements, it's beginning to look like a head
problem. I am reluctant to actually load the heads until I have to. I still
have not "cleaned" the top head thouroughly, although it seems clean
examining it through a loop.
I may just install a pair of known good drives in the machine and
troubleshoot these two independantly. At least I would have matching drives
in the machine until I can figure out what is wrong here.
Thanks,
Kelly
This past weekeend I found a ADIC 1200D DAT tape library in a scrap pile.
It has a Sony DAT-2 tape drive with an autochanger and holds up to 12
tapes. I'm thinking of using it on my PC. Can anyone recommend a good (and
cheap!) backup program that will work with Windows 98?
Joe
>From: "Dan Williams" <williams.dan(a)gmail.com>
>
>On Tue, 18 Jan 2005 10:16:11 -0800 (PST), Dwight K. Elvey
><dwight.elvey(a)amd.com> wrote:
>> Hi Randy
>> I've written special drivers for the floppies
>> under DOS in the past so that isn't a real
>> issue. I just wish it would work without me
>> having to pull out the reference books to
>> deal with it.
>> It works incorrectly in both MSDOS and PCDOS.
>> It is just annoying. The /u should mean just that,
>> unconditionally format.
>> Dwight
>>
> In MSDOS the /u doesn't actually mean unconditional in the normal
>sense. It means do not save unformat information, it will still stop
>if it gets errors.
>
>Dan
>
Hi
Sure but what about not reading track 0 before formatting
means it should abort the formatting without first doing
a low level format of that track. It is just stupid.
If I completely erase the track, it formats just fine.
As Sellam says, it is just stupid design.
Dwight
This is not an AMI chip. It is from a small foundry in Canada that was the
first second source for intel memory chips. I was informed of the name a couple
years ago when I sold some of these on epay. But did not save it. Perhaps
someone on the list knows.
My 1101s were from 1973. I think the foundry only existed for about three
years in the early 70s.
Paxton
Astoria, Oregon
PS, If you want to part with any I am interested.
>I know. It's another one of those stupid things that MS did with DOS that
>makes absolutely no sense. Just format the damn disk and report any
>errors for the USER to decide.
>
>I once came across some program on the WWW that supposedly rehabilitates
>such disks (most likely by doing an LLF on track 0) but unfortunately I
>never bookmarked it.
I used to run into this all the time. When you format a floppy for the
Mac, DOS will then report the Track 0 error and refuse to reformat it. I
always just formatted the disk for DOS on my Mac to get around the
problem (and then got really irked when I was told "The mac is not
compatible with anything else"... REALLY, not only can I read/write PC
disks, but I could read/write all the PC users files long before any of
them had tools to deal with Mac files!)
-chris
<http://www.mythtech.net>
>From: "Dave Dunfield" <dave04a(a)dunfield.com>
>
>>I once came across some program on the WWW that supposedly rehabilitates
>>such disks (most likely by doing an LLF on track 0) but unfortunately I
>>never bookmarked it.
>
>When I was selling my software on diskette, I wrote my own tools for diskette
>duplication, using a Victory autoloader - I also boiled-down the core functions
>into a one-at-a-time disk command line duplicator that works with standard
>floppy drives called XDISK.
>
>Like most disk-to-file copiers it will read a complete image of the floppy
>track by track into a disk file - unlike most file-to-disk copiers, it
>will low-level format, write, and verify each track in a single pass as it
>writes the file back to a disk. It does not care *WHAT* is previously on the
>disk, as the first command it issues on each track is "format track".
>
>This can be used to restore disks that DOS refuses to format due to problems
>in track-0 (just write out a blank floppy image) - I can send it to you if
>you like (runs under any version of DOS).
>
>Regards,
>Dave
>--
>dave04a (at) Dave Dunfield
>dunfield (dot) Firmware development services & tools: www.dunfield.com
>com Collector of vintage computing equipment:
> http://www.parse.com/~ddunfield/museum/index.html
>
>
>
My only issue there is that I'm never sure how big to make
the various gaps.
Anyway, the strong magnet works, it is just a hassle.
Dwight
Hi Randy
I've written special drivers for the floppies
under DOS in the past so that isn't a real
issue. I just wish it would work without me
having to pull out the reference books to
deal with it.
It works incorrectly in both MSDOS and PCDOS.
It is just annoying. The /u should mean just that,
unconditionally format.
Dwight
>From: "Randy McLaughlin" <randy(a)s100-manuals.com>
>
>From: "Dwight K. Elvey" <dwight.elvey(a)amd.com>
>> Hi
>> DOS has an irritating feature when asked to format
>> a disk. If track 0 is partially readable it will
>> fail to format, even if you use the /u option.
>> I've been moving data from one machine to another
>> and the source machine has a flaky drive. It sometimes
>> trashes track 0.
>> I've found that the only way to get around this problem
>> is to wipe the disk with a strong magnet.
>> Why can't it just try to format first and then check
>> track 0. Why must it fail to format because track 0
>> is partially readable when I specifically asked it
>> to unconditionally format?
>> Dwight
>
>Try picking up the format program from freedos/opendos and see if it does
>the same. If needed it may be able to be modified.
>
>
>Randy
>
>
>
>I once came across some program on the WWW that supposedly rehabilitates
>such disks (most likely by doing an LLF on track 0) but unfortunately I
>never bookmarked it.
When I was selling my software on diskette, I wrote my own tools for diskette
duplication, using a Victory autoloader - I also boiled-down the core functions
into a one-at-a-time disk command line duplicator that works with standard
floppy drives called XDISK.
Like most disk-to-file copiers it will read a complete image of the floppy
track by track into a disk file - unlike most file-to-disk copiers, it
will low-level format, write, and verify each track in a single pass as it
writes the file back to a disk. It does not care *WHAT* is previously on the
disk, as the first command it issues on each track is "format track".
This can be used to restore disks that DOS refuses to format due to problems
in track-0 (just write out a blank floppy image) - I can send it to you if
you like (runs under any version of DOS).
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
A good MS-DOS program to use to transfer files off an old computer is Xport
(search on Google for XPORT21). It includes a procedure to send itself over
a serial line to the target computer, so you don't need to have a working
floppy. It also includes instructions on wiring the cable.
Bob
Date: Sat, 15 Jan 2005 12:09:37 -0600
From: Jim Leonard <trixter(a)oldskool.org>
Subject: Re: Data recovery on Toshiba T3100 laptop
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk(a)classiccmp.org>
Message-ID: <41E95C61.5000901(a)oldskool.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Tore S Bekkedal wrote:
>I have a VGA monitor, no CGAs around, but I also have a 9-pin to 15-pin
>male-male cable - but aren't the voltages different?
Voltages aside, the technologies are completely different; it won't work. I
would follow the "boot-a-floppy-and-transfer-via-kermit" method. Or use a
DOS-based program like FastLynx or even the built-in transfer in DOS 6.x's
intersvr/interlnk programs.
--
Jim Leonard (trixter(a)oldskool.org)
http://www.oldskool.org/
Want to help an ambitious games project?
http://www.mobygames.com/
Or check out some trippy MindCandy at
http://www.mindcandydvd.com/