1541 drive alignment/repair

[frank]

Hi all,
for some projects, I need a spare 1541 drive other than my original and still
perfectly functional one.
I have a 1541-II lying around, and it worked the first time I tried it (that
was yesterday). Now it doesn't read any disk anymore.
I downloaded the fine commodore 1541 troubleshooting and repair guide and
it has procedures based on the "Dysan Analog Alignmnet diskette 224/2A".
Now I guess this one is next to impossible to get nowadays, right?
There're similar procedures not requiring this particular disk, but I
thougth asking does no harm :)
Is anyone still able to align and troubleshoot a real 1541 (and similar)
or everyone switched to SD cards and modern stuff?
Thanks
Frank

[Snogpitch]

I've had reading problems with my 1541-II over the years. Every time it was because the pressure of the read head was not getting adequate contact on the surface of the disk. Lightly bending the lever mechanism to allow greater pressure restores reading functionality unit it is needed to be done again in a few years.
An easy way to check if this is your problem is to try to read the directory with your finger lightly pressing on the drive head. If it reads, the that's your problem.

Snogpitch

ICQ: 4989342

[B00ze]

On 2016-06-25 03:49, frank <fr...@invalid.net> wrote:

> I downloaded the fine commodore 1541 troubleshooting and repair guide and
> it has procedures based on the "Dysan Analog Alignmnet diskette 224/2A".
> Now I guess this one is next to impossible to get nowadays, right?

Vorpal, if I recall, also came with an alignment disk - I used to have
one. The problem is that you can't copy this disk, because then the disk
acquires the alignment of the drive that wrote it (but if you copy it on
a perfect drive then you're good).

This guy had some for sale last year:
http://www.lemon64.com/forum/viewtopic.php?t=55340

Regards,

--
! _\|/_ Sylvain / B00...@hotmail.com
! (o o) Member:David-Suzuki-Fdn/EFF/Red+Cross/SPCA/Planetary-Society
oO-( )-Oo "I do not fear computers, I fear the lack of them." -Asimov

[frank]

Snogpitch <snog...@prodigy.net> wrote:
> I've had reading problems with my 1541-II over the years. Every time it was
> because the pressure of the read head was not getting adequate contact on
> the surface of the disk. Lightly bending the lever mechanism to allow
> greater pressure restores reading functionality unit it is needed to be
> done again in a few years.

nice tip! Thanks, I'll try tomorrow. I spent the last two days fixing two
SX-64 drives, both with only mechanical issues. One had a lazy belt and needed
real cleaning and one needed only cleaning but I forgot to check the spindle
speed before burying again into the worst SX-64 version that you can encounter
in your life :(
One SX-64 version has 4 screws to remove the whole FD+box stack without
touching almost anything else (well you need to unscrew the cartdrige
connector too).
Another version requires you to almost remove everything to unscrew the 4
drive screws and this includes: monitor, bottom cover, all cables from
motherboard plus VIAs board, motherboard and VIAs board (of course),
power supply, cartdrige connector. Oh, and once you finally remove the screws,
you understand that you need to remove the whole front panel too.
I'm not going to do it again, it will be a marginal FD for ever.

> An easy way to check if this is your problem is to try to read the directory
> with your finger lightly pressing on the drive head. If it reads, the that's
> your problem.

Great, thanks again. I was suspecting the power supply since I see some line
frequency noise on the spindle waveform, but I hadn't the correct connector
to make a compatible (and serious) power supply, so I left it alone.
I hope it's really this mechanical tip as it was reading fine for one day
however.

Best of everything
Frank IZ8DWF

[frank]

B00ze <B00...@hotmail.com> wrote:
> On 2016-06-25 03:49, frank <fr...@invalid.net> wrote:
>
> Vorpal, if I recall, also came with an alignment disk - I used to have
> one. The problem is that you can't copy this disk, because then the disk
> acquires the alignment of the drive that wrote it (but if you copy it on
> a perfect drive then you're good).
>
> This guy had some for sale last year:
> http://www.lemon64.com/forum/viewtopic.php?t=55340

thanks for the informations. I'm reading most of the old repair guide,
so I guess that most of the repairs can be also made with a known good
factory made floppy (and I have a few that still read fine on all
drives). There aren't many shortcuts I think.
Clean the mechanics, check spindle speed and most important: check for
micro slips in the spindle belt if it's a belt driven spindle motor.
Then check head rails and maybe track-step alignment (but hard to be off
in most mechanics I've seen so far) and end-stop of the head movement.
I've had only one electronic failure on these drives, all seems to be
age-related on the mechanics.
Oh, and avoid "pressure to get the job done quickly", ever.

Frank IZ8DWF

[frank]

frank <fr...@invalid.net> wrote:
> Snogpitch <snog...@prodigy.net> wrote:
>> I've had reading problems with my 1541-II over the years. Every time it
>> was because the pressure of the read head was not getting adequate contact
>> on the surface of the disk. Lightly bending the lever mechanism to allow
>> greater pressure restores reading functionality unit it is needed to be
>> done again in a few years.
>

Just for the record, that was it!
The drive is ok now, formats, reads, everything's fine.

Thanks again!
Frank IZ8DWF

[J.B. Wood]

On 06/25/2016 07:30 PM, B00ze wrote:
> On 2016-06-25 03:49, frank <fr...@invalid.net> wrote:
>
>> I downloaded the fine commodore 1541 troubleshooting and repair guide and
>> it has procedures based on the "Dysan Analog Alignmnet diskette 224/2A".
>> Now I guess this one is next to impossible to get nowadays, right?
>
> Vorpal, if I recall, also came with an alignment disk - I used to have
> one. The problem is that you can't copy this disk, because then the disk
> acquires the alignment of the drive that wrote it (but if you copy it on
> a perfect drive then you're good).
>
> This guy had some for sale last year:
> http://www.lemon64.com/forum/viewtopic.php?t=55340
>
> Regards,
>

Hello, and I've still got two operating 1541s with the original long
circuit boards. (Still amazed that the drive belts never required
replacement after 30 years.) The only thing (other than alignment) that
ever went wrong was that I had to replace a failed voltage regulator in
one of them but that was a long time ago).

As for alignment, the original factory procedure required a special disk
and an oscilloscope. I have a package, "1541 Physical Exam" by Cardinal
Software that also has a special disk but you can do a complete
alignment just using the info displayed on the monitor. This package
also included two bent piano wire track 1 stops to replace the original
solid metal ones that were responsible for most 1541 drive alignment
problems. A lesser problem was when the spindle was not turning at the
required 300 rpm. Sincerely,

--
J. B. Wood e-mail: arl_1...@hotmail.com

[B00ze]

On 2016-06-27 06:54, J.B. Wood <arl_1...@hotmail.com> wrote:

> On 06/25/2016 07:30 PM, B00ze wrote:
>> On 2016-06-25 03:49, frank <fr...@invalid.net> wrote:
>>
>>> I downloaded the fine commodore 1541 troubleshooting and repair guide
>>> and
>>> it has procedures based on the "Dysan Analog Alignmnet diskette 224/2A".
>>> Now I guess this one is next to impossible to get nowadays, right?
>>
>> Vorpal, if I recall, also came with an alignment disk - I used to have
>> one. The problem is that you can't copy this disk, because then the disk
>> acquires the alignment of the drive that wrote it (but if you copy it on
>> a perfect drive then you're good).
>>
>> This guy had some for sale last year:
>> http://www.lemon64.com/forum/viewtopic.php?t=55340
>>
>> Regards,
>>
> Hello, and I've still got two operating 1541s with the original long
> circuit boards. (Still amazed that the drive belts never required
> replacement after 30 years.) The only thing (other than alignment) that
> ever went wrong was that I had to replace a failed voltage regulator in
> one of them but that was a long time ago).

You mean those things near the back, with the heat sinks? Yop, had one
of those die on me too.

> As for alignment, the original factory procedure required a special disk
> and an oscilloscope. I have a package, "1541 Physical Exam" by Cardinal
> Software that also has a special disk but you can do a complete
> alignment just using the info displayed on the monitor. This package
> also included two bent piano wire track 1 stops to replace the original
> solid metal ones that were responsible for most 1541 drive alignment
> problems. A lesser problem was when the spindle was not turning at the
> required 300 rpm. Sincerely,

The Vorpal tool reads the alignment disk (it moves the head back and
forth over about 2 tracks, constantly) and reports an alignment number.
You can then unscrew the 2 screws holding the step motor and rotate it
slightly in one direction or the other. Screw it back and repeat the
test. It's coarse but it works, I did it several times (you can tell
you're ok when other people can read your disks again). The problem is
you'd need to use glue on those screws once you've played with them,
otherwise alignment drifts over time (unless you are able to screw those
screws really really tight).

Regards,

--
! _\|/_ Sylvain / B00...@hotmail.com
! (o o) Member:David-Suzuki-Fdn/EFF/Red+Cross/SPCA/Planetary-Society

oO-( )-Oo "Captain ... one ... harmless ... little ... Tribble?"

[J.B. Wood]

On 06/29/2016 12:33 AM, B00ze wrote:

> The Vorpal tool reads the alignment disk (it moves the head back and
> forth over about 2 tracks, constantly) and reports an alignment number.
> You can then unscrew the 2 screws holding the step motor and rotate it
> slightly in one direction or the other. Screw it back and repeat the
> test. It's coarse but it works, I did it several times (you can tell
> you're ok when other people can read your disks again). The problem is
> you'd need to use glue on those screws once you've played with them,
> otherwise alignment drifts over time (unless you are able to screw those
> screws really really tight).
>
> Regards,
>

Hello, and while I'm unfamiliar with Vorpal tool, the Cardinal Software
package I previously referenced displays a simple picket fence on the
monitor. The procedure is to get the asterisks displayed for several
tracks inside the fence using the supplied alignment disk while
carefully manipulating the drive head stepper motor mount back and forth
in very tiny increments. Then, if required, you adjust the spindle
motor potentiometer for 300 rpm (You don't need an alignment utility to
adjust spindle motor speed - just a fluorescent lamp to shine on the
strobe disk on the bottom of the spindle motor.)

I wouldn't recommend gluing down any screws as you mentioned. It'll
just create more work to do if you have to align the drive in the
future. I never had a problem with any screws coming loose on a 1541
stepper motor bracket. Granted, even with tight screws I can't say for
sure that the stepper motor bracket won't change position slightly over
a period of time. Knock out the head alignment a mere .001 inch and
you've got a problem. On the earlier 1541s a seek to track 1 (needed
for example when formatting a new disk) caused a pulley that was pressed
fitted on its shaft to slip over a period of time as the track 1 hard
metal stop was encountered. This was that banging noise that 1541 users
dreaded. Sincerely,

[nmp...@gmail.com]

I have hours in trying to fix my old drive. Lot of reading online but nobody else suggested this. Thanks, it helped me figure out the issue!