1541 Read error

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norm8332
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Re: 1541 Read error

Postby norm8332 » Thu Oct 26, 2017 3:20 pm

I mean a loadstar or other disk without protection. I use a c64 to align the drives. Here is the software shown in the video: http://commodore.software/downloads/download/26-disk-alignment-tools/117-1541-1571-alignment-system

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Re: 1541 Error

Postby eslapion » Fri Oct 27, 2017 10:51 am

groepaz wrote:afaik there is no difference in the material, so that would be really odd (and isnt it a 1541 compatible drive?)

I was never able to format a 5.25" floppy disk in a 1541. Some people reported it caused the destruction of the R/W of the drive when they tried repeatedly.

See:
http://www.retrotechnology.com/herbs_st ... .html#data

5.25 inch drives, 40 track (early drives 35 track)

...

Diskette and Media:
Mylar, 0.003 in thick (.0008mm)
iron oxide coating, 300 oersteds coercivity
same media for single and double density media

...


vs
5.25 inch drives, 1.2M HD, 80 track

...
HD media: cobalt coating, 600 oersteds coercivity
orientation of index hole: see previous 5.25" description
...
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srowe
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Re: 1541 Read error

Postby srowe » Fri Oct 27, 2017 12:01 pm

Floopy wrote:I have an oscilloscope, any solutions with that maybe?


The 1541 Technical Reference Pg 19 explains the procedure for head adjustment (not that I've ever done it).

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vicist
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Re: 1541 Read error

Postby vicist » Fri Oct 27, 2017 12:15 pm

I bought a mixed lot of sd and dd disks from ebay. They all looked in great shape.
No problem formatting and saving data to the sd disks but nothing doing with the dd ones which look brand new.

The drive has never let me down and reads all commercial disks.

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Re: 1541 Read error

Postby groepaz » Fri Oct 27, 2017 12:17 pm

eslapion wrote:I was never able to format a 5.25" floppy disk in a 1541. Some people reported it caused the destruction of the R/W of the drive when they tried repeatedly.

WAT. you are not making any sense. and i was referring to the supposed difference of SD and DD disks - not DD vs HD, which we all know is different, of course.
Floopy wrote:I have an oscilloscope, any solutions with that maybe?

simply said, just put the scope at the drive head and measure the amplitude. adjust for maximum amplitude with an "original" disk (test/demo disk is fine). you can probably read schematic when you own a scope :) so get them and perhaps measuring behind the r/w amplifier makes it a bit easier.
(this is the "ghetto method" which works fine for DD disks most of the time afterall - the "proper" method would be using a special alignment disk)
vicist wrote:No problem formatting and saving data to the sd disks but nothing doing with the dd ones which look brand new.

that sounds really odd - the 1541 is a DD drive afterall :)

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Re: 1541 Read error

Postby eslapion » Fri Oct 27, 2017 12:20 pm

groepaz wrote:WAT. you are not making any sense. and i was referring to the supposed difference of SD and DD disks - not DD vs HD, which we all know is different, of course.

You didn't include a quote of what you were answering to...
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vicist
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Re: 1541 Read error

Postby vicist » Fri Oct 27, 2017 1:08 pm

DOH!!!

Just checked my disks and then remembered that the listing was wrong. It was a mix of sd and hd disks, not sd and dd.

Sorry for the disinformation. :oops:

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Floopy
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Re: 1541 Read error

Postby Floopy » Fri Oct 27, 2017 2:27 pm

srowe wrote:The 1541 Technical Reference Pg 19 explains the procedure for head adjustment (not that I've ever done it).

I just noticed that I see that I need to hook the scope up on pin 9 on UC1(or UC2 I don't remember), and pin 7,8 UF3. Note that I have a "short" board. I have a few "factory" disk, so I will try to calibrate the drive using them. I will have to borrow an oscilloscope with a sync feature though (mine does not have one) , so it might take a week or two to try this out.
:!: Just saying this right now to avoid any further confusion, I use diskettes that where originally used on Apple II . I reformat them and use them without issues. :!:
Last edited by Floopy on Fri Oct 27, 2017 2:41 pm, edited 2 times in total.
-Floopy

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Floopy
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Re: 1541 Read error

Postby Floopy » Fri Oct 27, 2017 2:29 pm

norm8332 wrote:I mean a loadstar or other disk without protection. I use a c64 to align the drives[/url]

The disk I is only as good as the drive it was made with, I only own one 1541 drive.
-Floopy

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merser
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Re: 1541 Read error

Postby merser » Fri Oct 27, 2017 5:04 pm

Do you have the maintenance manual?
There is a lot of information on how to do available but I didn't see any that didn't need an alignment disk of some kind.

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiyrr_r8pHXAhVHwLwKHWexCiAQFgguMAE&url=http%3A%2F%2Feverythingcommodore.com%2Frequest.php%3Fpub_1541_maintenance_guide.pdf&usg=AOvVaw0lfsQmHhmbFOn2_EfwSMMK

This site mentions a method with an alignment disk or commercially prepared. I guess that could be any bought software disk?

http://sunfishdesigns.com/tcr/cbm/1541.html?i=1

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Re: 1541 Read error

Postby groepaz » Fri Oct 27, 2017 8:08 pm

You didn't include a quote of what you were answering to...

you can safely assume that if someone doesnt explicitly quote ... then he is directly answering to the previous post in the thread.

This site mentions a method with an alignment disk or commercially prepared. I guess that could be any bought software disk?
http://sunfishdesigns.com/tcr/cbm/1541.html?i=1


the second method described on that page equals the "ghetto method" using a scope. (creative way to do it too :)) for this you need a factory written disk, not an "alignment disk".

i wouldnt even try it with those alignment disks (like the freespirit one) that use only a program on the c64 to determine alignment... this is very inaccurate.
Last edited by groepaz on Fri Oct 27, 2017 8:11 pm, edited 2 times in total.

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Floopy
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Re: 1541 Read error

Postby Floopy » Fri Oct 27, 2017 8:11 pm

merser wrote:Do you have the maintenance manual?
This site mentions a method with an alignment disk or commercially prepared. I guess that could be any bought software disk?
http://sunfishdesigns.com/tcr/cbm/1541.html?i=1

That's what I'll end up doing since I don't own an alignment disk. I'm guessing the original software disk should at least give me a somewhat aligned head.
-Floopy

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Floopy
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Re: 1541 Read error

Postby Floopy » Sun Jan 21, 2018 1:01 pm

Reviving my own topic here...

I tried aligning my drive today. I got this and I'm not sure what I'm doing wrong. The probes are attached to UF4 pin 7,8. Any advice?
Sorry for the blurry pictures.
Attachments
EPSN0007.JPG
EPSN0006.JPG
-Floopy

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Floopy
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Re: 1541 Read error

Postby Floopy » Sun Jan 21, 2018 6:25 pm

Got a better picture
Attachments
EPSN0005.JPG
-Floopy

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Kakemoms
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Re: 1541 Error

Postby Kakemoms » Mon Jan 22, 2018 6:58 am

groepaz wrote:afaik there is no difference in the material, so that would be really odd (and isnt it a 1541 compatible drive?)


There is generally more difference between different manufacturers than between SD and DD. Most manufacturers probably moved to the DD process once they had better oxides (its thinner and thus cheaper).


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