What *do* people use to align a shugart drives? I have been ok adjusting the speed of drives but I dont adjust alignments.. I plan to learn more about the Dysan tester gear because this seems to be a popular repair module. Bigger picture, I have been sorting tools, testers, cables, etc. going through everything to better organize stuff so I dont accidentally dont double purchase or needlessly hold multiple items when I only need one of something. On Tue, Oct 1, 2024, 11:37 PM Mark Huffstutter via cctalk < cctalk(a)classiccmp.org&gt; wrote:

I assume it's not easy to copy alignment disks, but I guess I will find out. On Wed, Oct 2, 2024, 12:02 AM Mark Huffstutter via cctalk < cctalk(a)classiccmp.org&gt; wrote:

On Wed, Oct 2, 2024 at 10:01 AM geneb via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: Do you have a Dysan disk tester? b

Chuck had actually talked about how to make one on a VCF post a while back: https://forum.vcfed.org/index.php?threads/greaseweazle-v4-reading-m1-5-25-fl oppies-on-a-sa400a-drive.1242918/post-1380519. Didn't sound like it was going to be as easy as copying a disk... ;)

Floppy Alignment disks have analog signals of varying intensity recorded on them.  A flux detector like the greaseweazle is a binary (presence/absence) device. It also has off track signals on it.  I don't think there is any way to create them with anything but a specially modified drive connected to a special controller. On 10/2/2024 7:36 PM, Chuck Guzis via cctalk wrote:

Just curious if you had a known "good" drive, a golden unit so to speak, that was well aligned with an authentic alignment diskette-- could you then use that drive to write plain old data diskettes that the downstream users would then align their drives to? Could they simply maximize the read signal coming off that data diskette? I'd assume that the data written would include track number in the data so a piece of software could help ensure you are actually on the correct track while you are tweaking the gizmos to maximize the read signal. I'd assume you could get access to the raw read signal (before or after some read amplifier) on the drive and put your scope there to help you maximize that signal level. Wouldn't this result in aligning that user's drive to the sweet spot of the track(s) on the diskette if the assumption is that the data diskette was written with tracks in the right place? cje -- Chris Elmquist

On Thu, 3 Oct 2024, Jon Elson via cctalk wrote: Trivial enhancements: "Teaching grandma to suck eggs": use DOS, not Windows 11. Do a very thorough bulk erase. And then use a 96tpi drive to write to it, even if the target drive to be aligned is 48tpi. That will give you a narrower track, centered on where the wide track would have been. On a PC, rather than trying to make sense out of Microsoft's FORMAT program to modify it, it is not hard to go to Int13h and give it a format command. With NEC type of controller, you will need to set up a buffer containing a list of the sector header contents that you want. (with WD controllers, you create a track image and do a "WRITE TRACK") If the target drive to be aligned is 48tpi, and you use a 96tpi drive to make the test disk, use a "360K" or "720K 5.25" disk, NOT a "1.2M" drive, and remember that if you are going to write sector headers, to double the cylinder number. If you use a "1.2M" drive, be sure to set the motor speed to 300RPM, not 360 RPM and write at 250K bits per second, OR, with the motor speed at 360RPM, write at 300K bits per second. With analog alignment disks, you want at least a 20MHz scope; my NLS 215 portable scope was not adequate. -- Grumpy Ol' Fred cisin(a)xenosoft.com

It's a mechanical system, they're *all* old at this point. Some of them just go out of alignment from wear, heavy use, whatever. I've personally had TM-100s that came with systems I got in the mid 90s slowly become less and less reliable with reading diskettes written on other systems, or even sometimes ones written on that drive but 10+ years ago. Turned out to be marginal alignment. I wouldn't be surprised if drives also become more sensitive to marginal alignments as everything in them ages -- something like lower head output levels, sloppier stepper positioning, etc. In particular, I've had drives where the azimuth alignment ends up out, and on drives with non-adjustable azimuth I do wonder if they were just not super well aligned from the factory and finally wore enough to be out. I have not done extensive failure analysis as I use those drives which have uncorrectable alignment issues as parts to fix other drives (I now have a couple TM-100s where the only original parts are the frame and wiring!) Then there are of course alignment issues caused by break-fix repairs, like replacing an index sensor, a head carriage guide rod (even if you're careful you can knock it out of alignment), stepper replacement/new bearings, or anything where the carriage actually gets fully removed. Yes. If you want an alignment that allows reliable interchange, you need to align with an AAD. I have had to realign several "good enough using ImageDisk's beep alignment" hobbyist jobs done with factory written diskettes. With the AAD, it's immediately obvious that the alignment was marginal. You could do a media interchange dance between all of your available drives, but you'd still be in the position of maybe being misaligned to everyone else in the world :P If you don't care about interchange, the only really critical alignment is index alignment on hard sectored drives. That needs to be within tolerances or else you'll get missed sectors around the index. Some drives also have adjustable index skew, which is a special consideration of index alignment (e.g. Pertec FD-400 and FD-500 series, with leadscrews that are unsupported on the hub end) Thanks, Jonathan

Even our older Tek DSO does poorly with the analog alignment patterns...not just the "cat's eye" radial alignment pattern, but also the azimuth bars. Index burst is "good enough" on it and sometimes the ability to introduce large, precise trigger delays makes it the more suitable tool (like for some alignments where we don't have the correct, factory-specified AAD and have to calculate the index offset). The old Tek 465 does excellent though :P Thanks, Jonathan

question: could somebody (did they at the time) write a program for the apple ][ to create such a diskette? The apple drive can do half track stepping, and IIRC the signal is written strictly by a timing loop in the program <pre>--Carey</pre>

A small laser interferomenter and a screw driver could be used, once one determined the center of the track by magnetic material and a microscope. Some what special equipment but not all that special, now days. Years ago, I went to a Seagate building to help a friend with a servo writer problem. It only took a few minutes so I never charged them. Of interest here was that they used a stepper motor to control the position of the head. The problem was that they wanted to turn the power off to the stepper motor to remove an stray magnetic fields. They did it too soon while the motor was still in motion, causing the motor to not stop at the desired location. Adding some delay solved that one. So, the point is that a stepper was enough for a hard drive servo track. Of other interest, they were using an AIM 6502, running figForth. The programmer was obviously a previous BASIC programmer because he'd named vaiables with names like A, B, ... , instead of meaningful names that would have made the code more readable. Dwight ________________________________ From: Jonathan Chapman via cctalk &lt;cctalk(a)classiccmp.org&gt; Sent: Thursday, October 3, 2024 4:11 AM To: General Discussion: On-Topic and Off-Topic Posts &lt;cctalk(a)classiccmp.org&gt; Cc: Jonathan Chapman &lt;lists(a)glitchwrks.com&gt; Subject: [cctalk] Re: Dysan Alignment and Performance Testers Not really. Merely half-stepping a drive wouldn't be accurate enough, plus you need to be able to drive not-data waveforms into the heads. --snip--

On Thu, 3 Oct 2024, Chuck Guzis via cctalk wrote: An analog alignment disk would be an impressive task. Something similar to the Dysan Digital Diagnostic Disk would be far more straight forward, starting with modifying a drive to be able to do precise (micrometer) postitioning of the head away from the normal position. Although far less precise and accurate than the analog alignment disk, . . radial alignment is done by seeing which off center tracks the drive can read. and adjusting it until it can read the same amount off-center in both directions. If it can read disks off-center in one direction better than disks off-center in the other diraction, that tells you which direction the head/positioner needs to be moved. The REAL dysan Digital Diagnostic Disk puts sectors on one track progressively further out of position in alternating sides; calling for reading an equal number of even numbered and odd numbered sectors. THAT would be difficult, but recording entire tracks off alignment by a known amount isn't so hard. Some of the old-timers might remember a guy who was on this list a long time ago, who claimed that the "copy-protectin defeating" program that he used could copy ANYTHING, even alignment disks! 'course, he was also the one who claimed that his 1990's "Sentry 7?) machine was the one that email had been "invented" on, that Valtrep was the predecessor to FORTRAN, and that he had a tape of OS/2 for the PDP(labeled "PDP OS/2"). Some of us speculated that that MIGHT actually be a backup tape from somebody having been using a PDP to develop some software to run under OS/2 -- Grumpy Ol' Fred cisin(a)xenosoft.com

On Wed, 2 Oct 2024, Glen Slick via cctalk wrote: Sorry.

On Thu, 3 Oct 2024 at 02:39, Fred Cisin via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: Ohhh yes. Dan Gahlinger, I think. That was quite funny. -- Liam Proven ~ Profile: https://about.me/liamproven Email: lproven(a)cix.co.uk ~ gMail/gTalk/FB: lproven(a)gmail.com Twitter/LinkedIn: lproven ~ Skype: liamproven IoM: (+44) 7624 227612: UK: (+44) 7939-087884 Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053

The appropriate alignment diskette, an *analog* oscilloscope, and a program to step the drive around and load heads. For most drives, that's a PC and ImageDisk, but we use a DeRamp FDC+ and AFEXER for Pertec drives in MITS disk systems. Seems we're one of the few places that will still do it for other people. I know of two other hobbyists who can align their own drives, but neither will do it for other people anymore, I think. Be *very* *careful* mounting an alignment diskette in a drive. If you frag it, there's no getting it back. They can't be written using a regular drive. When repairing a drive, I run it in whatever alignment it is, and read/write a lot of test data to make sure it's not about to wreck my alignment diskette with an errant write. After it is 100% functional, then it gets aligned. Thanks, Jonathan

On Wed, Oct 2, 2024 at 4:53 AM Bill Degnan via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: I only ever try to align a drive using an 'catseye' alignment disk. I have a little drive exerciser unit badged 'RS'[1] which will let me move the head around to seek to the alignment pattern track on the disk, etc. I can use that with a normal 'scope. [1] One of the large industrial electronic component suppliers in the UK, been around for not quite 90 years. 50 years ago they were 'Radiospares' which gives an idea how they started. But more often I use a thing called a 'Microtest'. This is a module containing an 8035 microcontroller, ADC and a serial port. It works with any IBM PC (I think the minimum spec is 256K RAM, any video card even MDA, and an RS232 port). I use an old Amstrad PPC640 'laptop' where the second floppy drive has been replaced by a DC37 socket. Basically you connect the drive-under-test to the PC as B:. Then plug the Microtest unit into the PC serial port and run the Microtest software. You select the drive type from a menu, it then shows a layout of the drive PCB (using the IBM line-drawing characters) showing where to connect 5 leads from the microtest unit (ground, index, track 0 sensor, differential outputs of the read amplifier). You can then do various tests -- spindle speed head alignment, index position, track 0 sensor position, etc) some of which use the standard catseye alignment disk. -tony

Not possible. The alignment requires a physical diskette. Thanks, Jonathan