Calibration and Alignment of DUODISK

[GianDO]

Hi everyone,

I have a Apple IIe. I'd like to know if it is possibile find a specific diagnostic software for the step motor calibration and adjustment of the heads alignment of DUODISK drive ..

 

Thank you

 

GianDO

[GameGeezer]

On 11/18/2021 at 5:15 PM, GianDO said:

Hi everyone,

I have a Apple IIe. I'd like to know if it is possibile find a specific diagnostic software for the step motor calibration and adjustment of the heads alignment of DUODISK drive ..

 

Thank you

 

GianDO

You need no more than an incandescent lamp. There are two rings on the spindle. The outside ring is 60Hz and the inside 50Hz. Use an incandescent bub and tune. When the ring sees to stand still, it is in spec.

 

If you are a PAL/50Hz region (Europe parts of Japan South America), use the inner ring. In the US, 60Hz Japan or other 60Hz regions use the outer ring.

[GianDO]

On 11/23/2021 at 2:16 PM, GameGeezer said:

You need no more than an incandescent lamp. There are two rings on the spindle. The outside ring is 60Hz and the inside 50Hz. Use an incandescent bub and tune. When the ring sees to stand still, it is in spec.

 

If you are a PAL/50Hz region (Europe parts of Japan South America), use the inner ring. In the US, 60Hz Japan or other 60Hz regions use the outer ring.

Ok instead of the lamp I used a laser tachometer and I managed to adjust the rotation speed. Unfortunately I discovered that I also have the head misaligned. Is there a way to adjust the heads? Are there any video tutorials showing how to do it? I have tried using APTest and would like to know if there are other software better than this one. Thanks.

[GameGeezer]

On 11/27/2021 at 11:34 PM, GianDO said:

Ok instead of the lamp I used a laser tachometer and I managed to adjust the rotation speed. Unfortunately I discovered that I also have the head misaligned. Is there a way to adjust the heads? Are there any video tutorials showing how to do it? I have tried using APTest and would like to know if there are other software better than this one. Thanks.

If you mean radial head misalignment, you must adjust the stepper motor. I have docs for the early drives on this procedure but thay are useless without a scope, and possibly old proprietary SW.

 

See PDF page 10: https://mirrors.apple2.org.za/Apple II Documentation Project/Books/Sams ComputerFacts - Disk Drive Apple II.pdf

 

The DuoDisk is effectively the same as the Disk II in most regards. See also: http://www.apple2faq.com/knowledgebase/recalibrating-disk-drives/

 

apple_disk_ii_technical_procedures.pdf

Disk Alignment Aid (N-D-N) (P-N 652-0199).dsk

Edited December 2, 2021 by GameGeezer

[GianDO]

On 12/2/2021 at 3:44 PM, GameGeezer said:

If you mean radial head misalignment, you must adjust the stepper motor. I have docs for the early drives on this procedure but thay are useless without a scope, and possibly old proprietary SW.

 

See PDF page 10: https://mirrors.apple2.org.za/Apple II Documentation Project/Books/Sams ComputerFacts - Disk Drive Apple II.pdf

 

The DuoDisk is effectively the same as the Disk II in most regards. See also: http://www.apple2faq.com/knowledgebase/recalibrating-disk-drives/

 

apple_disk_ii_technical_procedures.pdf 6.75 MB · 3 downloads

Disk Alignment Aid (N-D-N) (P-N 652-0199).dsk 140 kB · 3 downloads

Unfortunately, the Disk Alignment AID program only allows you to operate on drives connected via slot 6. My Duodisk is connected to slot 4. On slot 6 I put the only working drive Apple DISK ][ from which the program started ..

[GameGeezer]

On 12/4/2021 at 5:16 PM, GianDO said:

Unfortunately, the Disk Alignment AID program only allows you to operate on drives connected via slot 6. My Duodisk is connected to slot 4. On slot 6 I put the only working drive Apple DISK ][ from which the program started ..

Which drive is misaigned; d1 or d2?

Disk Alignment Aid (N-D-N) (P-N 652-0199).dsk

[Baldrick]

You need to use APTEST to align the drive.

APTEST's alignment routines are the only ones that can accomplish reasonable head alignment without specialized alignment diskettes or specialized instruments.

It does it with track edge (and half track) detection with the head moving in both directions.  It is a multi-iterative process (if you repeat the test several times you can close in on decent alignment).  Using more than one reference known-good diskette will also help get a good alignment.  I've aligned dozens of drives with this software with 100% success.

All you need are a speed-calibrated drive (there is a routine to help you calibrate speed, too) and a few known-good diskettes.  Preferably (non-copy protected) commercially made software disks that will have a higher chance of being written with drive duplicators having proper alignment.

Read the instructions carefully that are included in the software.  You can easily make a good drive non-functional with APTEST.

You can find APTEST here:  https://macgui.com/downloads/?file_id=9611&keywords=aptest

 

Oh, and if you put your good DISK-II in slot-7 and the DUODISK in Slot 6 you can still muck around with the software suggested above, but do yourself a favour and use APTEST.

 

[GianDO]

On 12/6/2021 at 3:05 PM, GameGeezer said:

Which drive is misaigned; d1 or d2?

Disk Alignment Aid (N-D-N) (P-N 652-0199).dsk 140 kB · 1 download

They are both misaligned

[GianDO]

19 hours ago, Baldrick said:

You need to use APTEST to align the drive.

APTEST's alignment routines are the only ones that can accomplish reasonable head alignment without specialized alignment diskettes or specialized instruments.

It does it with track edge (and half track) detection with the head moving in both directions.  It is a multi-iterative process (if you repeat the test several times you can close in on decent alignment).  Using more than one reference known-good diskette will also help get a good alignment.  I've aligned dozens of drives with this software with 100% success.

All you need are a speed-calibrated drive (there is a routine to help you calibrate speed, too) and a few known-good diskettes.  Preferably (non-copy protected) commercially made software disks that will have a higher chance of being written with drive duplicators having proper alignment.

Read the instructions carefully that are included in the software.  You can easily make a good drive non-functional with APTEST.

You can find APTEST here:  https://macgui.com/downloads/?file_id=9611&keywords=aptest

 

Oh, and if you put your good DISK-II in slot-7 and the DUODISK in Slot 6 you can still muck around with the software suggested above, but do yourself a favour and use APTEST.

 

I used APTEST, but it is very difficult to be able to adjust the head following the instructions which in my opinion are not really clear, it would be better to have a video tutorial ..

[Baldrick]

When APTEST does an alignment pass it gives a couple of numbers.  The first is the "Fraction right" number.  This should always be 1.  If it's not 1 then the head is grossly misaligned.  If it is 1 then the drive was able to find all the tracks it was looking for.  The second number is "going" and the third number is "coming"

"Going" is the read result going from low to high tracks which is how the disk drive initializes tracks.  This number should be less than .1.

"Coming" is the read result from high tracks to low tracks, which is the opposite direction to how the disk initializes diskettes.  This number should be between .1 and .2.

 

The instructions also mention this:

"ADJUST BY MOVING CLOCKWISE IF YOUR DIFFERENCE NUMBERS WERE TOO NEGATIVE"

"ADJUST COUNTER-CLOCKWISE TO MAKE THE DIFFERENCES LESS POSITIVE."

 

What you're looking for is a "Fraction right" of 1 and "going numbers between .1 and .3.  That will get you into readability range.

 

If the "fraction right" is always zero, then I use the following technique to get the stepper motor into the right ballpark.

 

Initialize a DOS3.3 diskette with a known-good drive.

Put the newly initialized diskette into the bad drive, loosen both stepper motor holddown screws and then type in this program in BASIC (with DOS3.3 loaded):

 

10 ONERR GOTO 20

20 PRINT CHR$(4)"CATALOG,Sx,Dy":  REM "x" is the slot and "y" is the drive number of the questionable drive

30 GOTO 20

 

This forces the drive to continuously attempt to get a catalog listing of the diskette.  While it is grinding on track zero adjust the stepper motor slowly in one direction until you get a catalog reading.  If you never get a catalog reading slowly adjust it in the other direction.  If your read-write head works you should eventually get a catalog reading.  This will put your stepper motor into "the ballpark".  lightly tighten one of the holddown screws and then run APTEST and follow the directions.

 

[GianDO]

17 hours ago, Baldrick said:

When APTEST does an alignment pass it gives a couple of numbers.  The first is the "Fraction right" number.  This should always be 1.  If it's not 1 then the head is grossly misaligned.  If it is 1 then the drive was able to find all the tracks it was looking for.  The second number is "going" and the third number is "coming"

"Going" is the read result going from low to high tracks which is how the disk drive initializes tracks.  This number should be less than .1.

"Coming" is the read result from high tracks to low tracks, which is the opposite direction to how the disk initializes diskettes.  This number should be between .1 and .2.

 

The instructions also mention this:

"ADJUST BY MOVING CLOCKWISE IF YOUR DIFFERENCE NUMBERS WERE TOO NEGATIVE"

"ADJUST COUNTER-CLOCKWISE TO MAKE THE DIFFERENCES LESS POSITIVE."

 

What you're looking for is a "Fraction right" of 1 and "going numbers between .1 and .3.  That will get you into readability range.

 

If the "fraction right" is always zero, then I use the following technique to get the stepper motor into the right ballpark.

 

Initialize a DOS3.3 diskette with a known-good drive.

Put the newly initialized diskette into the bad drive, loosen both stepper motor holddown screws and then type in this program in BASIC (with DOS3.3 loaded):

 

10 ONERR GOTO 20

20 PRINT CHR$(4)"CATALOG,Sx,Dy":  REM "x" is the slot and "y" is the drive number of the questionable drive

30 GOTO 20

 

This forces the drive to continuously attempt to get a catalog listing of the diskette.  While it is grinding on track zero adjust the stepper motor slowly in one direction until you get a catalog reading.  If you never get a catalog reading slowly adjust it in the other direction.  If your read-write head works you should eventually get a catalog reading.  This will put your stepper motor into "the ballpark".  lightly tighten one of the holddown screws and then run APTEST and follow the directions.

 

I followed your method, I booted dos 3.3 from the good drive and inserted a copy in the bad drive, I loosened the screws of the stepper motor and after some trying I managed to get a catalog, at least this way I am sure that the drive head and electronics are functional. At this point I tightened one of the screws as you suggested.

Apparently, however, the fact that I managed to obtain a catalog does not mean that the head is aligned, in fact any other command I issue (other than CATALOG) the drive is misaligned and if I try to re-enter the CATALOG command I get an "Error I / O ", then I have to do the previous operation all over again until I get a catalog back.

Once I got the catalog back, I tried to start APTEST, but the Fraction right turns out to be 0 as well as the others. At this point what should I do? Should I still act on the screws of the stepper motor by loosening the one I had tightened and moving clockwise and / or counterclockwise until obtaining a Fraction right = 1?

[Baldrick]

On 12/8/2021 at 4:26 PM, GianDO said:

I followed your method, I booted dos 3.3 from the good drive and inserted a copy in the bad drive, I loosened the screws of the stepper motor and after some trying I managed to get a catalog, at least this way I am sure that the drive head and electronics are functional. At this point I tightened one of the screws as you suggested.

Apparently, however, the fact that I managed to obtain a catalog does not mean that the head is aligned, in fact any other command I issue (other than CATALOG) the drive is misaligned and if I try to re-enter the CATALOG command I get an "Error I / O ", then I have to do the previous operation all over again until I get a catalog back.

Once I got the catalog back, I tried to start APTEST, but the Fraction right turns out to be 0 as well as the others. At this point what should I do? Should I still act on the screws of the stepper motor by loosening the one I had tightened and moving clockwise and / or counterclockwise until obtaining a Fraction right = 1?

Without a "Fraction Right" of 1 then you don't have a drive that's aligned to your diskette.  Keep trying. 

If you manage to get a semi-consistent catalog then the next thing to do is verify the rotational speed with APTEST.

Then re-do the Alignment test.  You have to be persistent and patient. This is a multi-iterative process and as the instructions suggest, using multiple-known-good diskettes and repeating the alignment over and over will eventually get you homed-in on a good head alignment. 

With the stepper motor in a position that can read a catalog put a small pen-mark on the stepper motor and on the drive base adjacent to the stepper motor flange.  That way you can get back to your starting point after rotating it and checking alignment.  Move it in very small increments.  No more than the width of the pen-mark at a time and re-check the alignment with APTEST every time you move the head.  If you think that you're going in the wrong direction, move it back to the starting point and slowly work the other way.  Eventually you'll get it.

 

Edited December 14, 2021 by Baldrick

[GianDO]

18 hours ago, Baldrick said:

Without a "Fraction Right" of 1 then you don't have a drive that's aligned to your diskette.  Keep trying. 

If you manage to get a semi-consistent catalog then the next thing to do is verify the rotational speed with APTEST.

Then re-do the Alignment test.  You have to be persistent and patient. This is a multi-iterative process and as the instructions suggest, using multiple-known-good diskettes and repeating the alignment over and over will eventually get you homed-in on a good head alignment. 

With the stepper motor in a position that can read a catalog put a small pen-mark on the stepper motor and on the drive base adjacent to the stepper motor flange.  That way you can get back to your starting point after rotating it and checking alignment.  Move it in very small increments.  No more than the width of the pen-mark at a time and re-check the alignment with APTEST every time you move the head.  If you think that you're going in the wrong direction, move it back to the starting point and slowly work the other way.  Eventually you'll get it.

 

Today I managed to get a catalog again. Trying other floppy disks (DOS3.3) I can see the catalog.
I ran the rotational speed test with APTEST, but it gives me completely out of order values eg. -15450 RPM. Intrigued, I wanted to measure the rotation speed with a tachometer and the value is correct, that is about 300RPM (299.5 - 300.5). So is there something weird about APTEST?
I would like to understand before making other attempts at head alignment if APTEST is reliable. Could it also be an electronic problem?

[Baldrick]

APTEST measures rotational speed by writing a marker on the diskette itself, reading it back and testing it against a timer.

Every other utility to measure speed does it in a similar fashion.  

I use the fluorescent lamp method (a fluorescent lamp shone on the spindle strobe sticker) to get the speed in the ballpark and then fine tune it with APTEST or Locksmith.

If you're unsure of APTEST's speed utility reliability, use Locksmith 6.0: https://mirrors.apple2.org.za/ftp.apple.asimov.net/images/disk_utils/locksmith/, or MECC's computer Inspector: https://mirrors.apple2.org.za/ftp.apple.asimov.net/images/educational/mecc/MECC-A240 Computer Inspector v1.0 (4am crack).zip to verify.

[GianDO]

4 hours ago, Baldrick said:

APTEST measures rotational speed by writing a marker on the diskette itself, reading it back and testing it against a timer.

Every other utility to measure speed does it in a similar fashion.  

I use the fluorescent lamp method (a fluorescent lamp shone on the spindle strobe sticker) to get the speed in the ballpark and then fine tune it with APTEST or Locksmith.

If you're unsure of APTEST's speed utility reliability, use Locksmith 6.0: https://mirrors.apple2.org.za/ftp.apple.asimov.net/images/disk_utils/locksmith/, or MECC's computer Inspector: https://mirrors.apple2.org.za/ftp.apple.asimov.net/images/educational/mecc/MECC-A240 Computer Inspector v1.0 (4am crack).zip to verify.

I have already tried to use Locksmith, the problem is that once started from a working drive it does not allow you to change the slot to choose the drive that does not work. The same happens with Computer Inspector.

Edited December 15, 2021 by GianDO

[Baldrick]

Not true.

Locksmith lets you select which drive to check the speed of (screen1.tiff)Screen1.tiff.  And so does MECC's computer inspector (screen2.tiff)Screen2.tiff

 

Screen1.tiff

Edited December 16, 2021 by Baldrick
addition

[GianDO]

1 hour ago, Baldrick said:

Not true.

Locksmith lets you select which drive to check the speed of (screen1.tiff)Screen1.tiff.  And so does MECC's computer inspector (screen2.tiff)Screen2.tiff

 

Screen1.tiff 20.18 kB · 3 downloads

I put the only working drive on slot 6 and the DUODISK drives on slot 4. Both of the software you suggest allow me to select drive 1 or drive 2, but only from slot 6 ..

[Baldrick]

22 hours ago, GianDO said:

I put the only working drive on slot 6 and the DUODISK drives on slot 4. Both of the software you suggest allow me to select drive 1 or drive 2, but only from slot 6 ..

OK, try Apple Cillin for drive speed testing then.cillin.tiff

 

Here's a disk image of it.

Apple-Cillin II.dsk

[+acadiel]

Just following back here with this document for APTest - there's some great instructions here.

 

 APPENDIX B: DOCS-ON-DISK FOR APTEST TRACK-CENTERING


       These docs appear when selected from the APTEST menu. They are
reproduced here to facilitate printing a paper copy.  Also, some users
might prefer the 80 column text display rather than the 40 column display
on the APTEST file.


                                 A.P.P.L.E.
                                 PRESENTS

                               DISK - DRIVE
                            RELATIVE ADJUSTMENT

                                    BY
                              CHARLES SUITOR

                                  (1980)



       This program does not measure the absolute alignment of a disk.  It
does measure the relative alignment between a drive and any diskette.
There is no standard set for the results presented here. However, we do
expect the results to be useful in several situations.

       The slot and drive that you wish to test will be requested.  The
program will then try to read the diskette in that drive on many tracks
and between them.  After several seconds, the drive will stop and results
will be shown.

       The "fraction right" is the fraction that the data tracks were read
correctly, and should always equal 1.  The other numbers are results from
trying to read between two tracks.  They are the fraction of times the
higher track was read minus the fraction the lower track was read.

       The first difference is the average of all such tries. The one
labeled "GOING" comes from motion from low to high tracks, which is the
same direction that initialization occurs.  Thus, this number will usually
be small (less than .1 for a diskette tested in the same drive it was
initialized in.

       The difference marked "COMING" results from motion from high to low
tracks and is often .1 to .2 more positive than the "GOING" difference.

       However, these results will vary as much as .1 to .2 on successive
trials, so be sure to repeat any questionable tests.

       If the differences are greater than +0.9 or less than -0.9, then
the drive is reading one track consistently when it should be reading
between the two.  The drive that initialized the diskette is not
positioning its head where yours is.  This outcome suggests that the
alignment of the two is different.  That alone does not require any
action; diskettes can be read reliably with differences of 0.9 or more.
However, if you have trouble reading diskettes from a particular source,
and the difference on these diskettes is very high, then alignment may be
a problem.

       To see whether alignment is your problem, test diskettes from a
reliable source such as the Apple distribution disks.  Test as many as you
can; not even Apple is infallible.  If your differences are mostly .3 to
.4, then you are probably quite well aligned.  In that case, ask your disk
source to check his alignment!

       If your differences are much more than 0.3, then you may have
problems with diskettes from those who are off by similar amounts in the
other direction.  If you do have problems, then take the drive to a
reliable service facility to have the drive checked and realigned.

       There are many other disk problems besides alignment. If you have
trouble with disks when read by the same drive in which they were
initialed, then alignment is not the problem.  Many problems are caused by
work or otherwise defective diskettes.

    But if you have problems with diskettes from one drive not being
readable by another, then the following track-centering alignment tests
may help you isolate your problem.


                            ALIGNING THE DRIVE

       If you are doubtful about this procedure, then please do not
attempt it!  These instructions are not official, authoritative, or
otherwise blessed!  No warranty is made as to their accuracy or
applicability.  We recommend that you take your drive to an authorized
service dealer.  The purpose of these instructions is to share our
experience with other fools who would tinker with their drive despite all
advice to the contrary.

       You can damage the drive by shorting the leads or test points.  You
can put the drive into worse alignment than it is now.  You can void the
warranty!

       1. Remove the top cover of the drive.
       2. Remove the bottom cover of the drive.

       On the bottom of the drive is a stepping motor, secured on two
sides with screws (bolts).  These bolts are in slots so that the motor can
rotate slightly when the bolts are loose.  This rotation of the stepping
motor in the slots is the alignment adjustment.

       Adjust by moving clockwise if the difference numbers were too
negative and you wish to make them more positive.  Adjust
counter-clockwise to make the differences less positive.  Not much
movement is needed!  It is difficult to make positional adjustments of the
stepping motor that will change the differences by less than 0.3.

       3. Make the desired adjustment on the stepper motor bolts.
       4. Check the alignment with the APTEST disk.
       5. Repeat steps 3 and 4 until the difference score is sufficiently
          low: a difference score of 0.4 or less.
       6. Reassemble the disk drive when finished.



       -------------------------------------------------------------
                   TRACK-CENTERING ALIGNMENT DATA SCREEN


       FRACTION RIGHT = _______

       THE FRACTION RIGHT SHOULD BE EQUAL TO 1.

       DIFFERENTIAL FRACTION = ______

       DIFF. FRACTION GOING = ______

       DIFF FRACTION COMING = ______


THE DIFF. FRACTIONS, ESPECIALLY THE "GOING" ONE, SHOULD BE
WITHIN +/- .4 IF THE DISKETTE IS ALIGNED WELL WITH THE DRIVE.


       -------------------------------------------------------------

 

[odingalt]

Hi folks, I had an Apple IIC disk drive and the AP68 stepper motor had an internal failure (failed solder from external wiring to inductor windings).  I repaired it and reinstalled the stepper motor but now my head is all out of alignment.  Does anyone have the mysterious APTEST software?  The link above is a dead link now, and not available on archive.org either.  Much obliged, the APTEST sounds like the right tool along with the other tips you posted to get myself back into alignment!

[odingalt]

23 hours ago, odingalt said:

Hi folks, I had an Apple IIC disk drive and the AP68 stepper motor had an internal failure (failed solder from external wiring to inductor windings).  I repaired it and reinstalled the stepper motor but now my head is all out of alignment.  Does anyone have the mysterious APTEST software?  The link above is a dead link now, and not available on archive.org either.  Much obliged, the APTEST sounds like the right tool along with the other tips you posted to get myself back into alignment!

Found it.  Current resting place: https://mirrors.apple2.org.za/ground.icaen.uiowa.edu/Collections/Buggie/

 

Note that it's a .SDK which needs to be converted using CiderPress https://a2ciderpress.com/