Commodore.ca: The PET, VIC, 128, 64 & More Forum

Well, my 1541 disk drive has finally ended up grinding it's way out of alignment after 20+ years of service. The drive is still in excellent condition and hasn't failed me before this issue. It'd be a shame to get rid of this drive for this single problem. Is there any simple way to realign th drive, or buy a 5 1/4 disk that can fix this? Thanks for your help.

Okay, new question. How do you reformat a disk? Never had to do this in the past, which was stupid of me. Thanks for your help

From the 1541 user guide, which you can find here: http://project64.c64.org/index.htm

4.2 NEW

This command is necessary when using a diskette for the first time.
The NEW command erases the entire diskette, it puts timing and block
markers on the diskette and creates the directory and BAM. The NEW
command can also be used to clear out the directory of an already-
formatted diskette. This is faster than re-formatting the whole disk.

FORMAT FOR THE NEW COMMAND TO FORMAT DISK:

PRINT#15, "NEW:name,id"

or abbreviated as

PRINT#15, "N:name,id"

FORMAT FOR THE NEW COMMAND TO CLEAR DIRECTORY:

PRINT#15, "N:name"

The name goes in the directory as the name of the entire disk. This
only appears when the directory is listed. The ID code is any 2
characters, and they are placed not only on the directory but on every
block throughout the diskette. That way, if you carelessly replace
diskettes while writing data, the drive will know by checking the ID
that something is wrong.

Great! Thanks a lot!

wildtiel wrote:Is there any simple way to realign th drive, or buy a 5 1/4 disk that can fix this? Thanks for your help.

The expert way to align the drive is with the use of an oscilloscope. The more or less amateur way to align the drive is to buy a disk that provides a means of aligning it (if you can get the program loaded), such as the 1541 alignment disk provided by Cardinal Software.

Truly,

Quick question: how many 1541s (or 1541-IIs) can a person daisy-chain together on their C64?

Update:

Oops... never mind. I believe I found the answer: Devices 8 thru 15 (software), 8 thru 11 (dip switches). Right?

Well, now that I found out that I can't even format a disk with the drive i have, I am thinking I have an even larger issue than I origionally thought. Is this something I should even bother trying to fix? Should I try to replace some of the chips inside? Some were way hotter than the others after only a few minutes of the drive being turned on. If so, where can I find replacement chips? Thanks a lot guys! i know these 1541's can be a lot of trouble.

I'd think that by the time you do all that you may have to do to fix your drive, you're better off buying a replacement.

There are a few resources on the Web where you can buy 1541s and 1541-II at reasonable prices.

Well, not considering time at all, which would cost less in the long run?

judland wrote:There are a few resources on the Web where you can buy 1541s and 1541-II at reasonable prices.

Our club sells 1541s for $5 each, not including shipping.

In Las Vegas right now,
Robert Bernardo
Fresno Commodore User Group
http://videocam.net.au/fcug
The Other Group of Amigoids
http://www.calweb.com/~rabel1/

Really? You think you can hook me up with a tested 1541 drive? I'd be very grateful .

wildtiel wrote:You think you can hook me up with a tested 1541 drive?

Sure! I will return on Tuesday night and can dig out a 1541 the next day. Where are you located?

Truly,

I'll PM you my address. I can not get the money right away. Will be going to the bank probably this weekend, so I'll let you know when I send out the payment.

Oh, and unless it already has cables included with it, i do not need them.

Thanks a lot!

Hi All,

I've bought a 1541-II drive recently, which is not willing to read and write (format) disks.
The drive powers up normally, without blinking fault codes on the front panel LED.
When trying to load the catalog the disk spins up, the R/W head moves to nearly the middle
of the tracks (probably to track#18), then a few moments later goes back to the outermost track,
and hits the limiter a few times. Then the spin stops and the drive LED indicates an error.
I got "21 Read error" message as a result of drive status query, and I have the very same message
after unsuccessful format attempts. The head was cleaned before these.

I guess it may not a head alignment issue, because it wouldn't affect the newly created disks.
I think it may be a head failure (broken read coil) or clogged air gap, or speed problem.
Other suggestions are welcome.

Unrelated to the issue, but why HD disks are not recommended for these drives?

And here comes the quiz:
Does someone faced with similar issues?
What should be the resistance of the R/W heads (according the schematics it consists two coils plus the erase)?
What peak voltage levels should be measured with an oscilloscope before the head amp?
Apart from the stroboscopic method (I'm not sure the strobe dial is available in the 1541-II too)
is it possible to check the speed with oscilloscope (e.g. a DC or PWM signal)?
In regard to the previous question: the disk speed is controled through DC or PWM method?

Thanks a lot !

Update: the drive is working now. I've made an X1541 cable and transferred a drive check program
to a disk.

Meanwhile I've managed to find out the answers to most my questions:
- I've checked the head resistances and they're normal, no short circuits
- Regarding the voltage output of the read head: I think this measurement will require a specially formatted disk,
because the output voltage is very low, which makes the oscilloscope readings very noisy, it's almost impossible to
recognize any patterns from the disk, containing "random-ish" data. Since the read error problem solved,
I stopped making further efforts.
- Speed check: there's no stroboscopic dial in the Newtronic drive. Because the drive check program was capable to
display disk RPM, the oscilloscope check method was dropped for now. I might try this later. (without a suitable
program only this or a laser RPM check could tell the actual RPM). The drive maintains 298.5 to 298.8 RPM which is
inside of the tolerance, so I've left it as is.

I'm still curious why HD disks aren't recommended? AnyOne?

I've started the treatment of the yellowed drive case here's the partial result: