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Floppy drive alignment tool?

shevett

shevett

Experienced Member
Joined
Jan 28, 2020
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Boston, MA
I was watching Adrian's Basement, and he used a tool that looks like it's helpful in aligning and tuning floppy drives. It set recording levels for the write head, speed checks, etc. Does anyone know what this tool is and/or has an image I can get? I have like 5 drives I'd like to get all tuned up and interchangeable, and while I can format/init on them, I'm not confident each can read the others' disks.
 
Dave Dunfield's ImageDisk (IMD):

It can be used carefully as an alignment tool.

In my experience, and what I usually see on those shows, are that floppy drives are dirty or in need of lubrication, and a few times, sensor issues. I would rule out as many of these simpler things out first, before going to alignment. Then study and get practice on what alignment means for your drive. There are ways to recognize alignment issues.

Also, reading each other disks is subjective. A 1.2MB high density drive can read and write a double density disk, but then it isn't interchangeable with a 360KB double density drive. There are also formatting, sectors, etc, and more. So there is more than alignment when it comes to being interchangeable. You might want to be more specific on what you hope to accomplish with your 5 drives and what they are.
 
The Spindle's RPM at 300 is VERY IMPORTANT. As is the Clamping force of the HUB so the
Media spins at the same speed. The Track Zero Detector must also be correct.

Alignment is always last priority.


TEZ has some good articles on Alignment you might be interested in reading.











Larry
 
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Thanks everyone. Mostly I need to make sure spindle speed and track alignment are correct - these are only the 140k Disk II drives that Franklin and Apple used, so there's no cross-compatibility issues that I'm working on (ie, the 1.2meg vs 360k issue). I just want to make sure the drives i have can talk to each other, and if I get soemoen elses disks, I can read them too.
 
I get that there are other ways to align a floppy drive other than those alignment disks that show up rarely and are high priced - I have read this thread. For use with drives common to machines like the TRS-80 or early PCs, has nobody been able to duplicate the signals and put them on a diskette?

I remember back when I had a C64 there was such a disk and it worked.
 
You can also use an incandescent lamp and the "stroboscopic" timing marks on the bottom of the Disk ][ drive spindle to get the speed properly tuned. I was able to get a drive that would not boot working that way. It works!
 
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epooch said:
You can also use an incandescent lamp and the "stroboscopic" timing marks on the bottom of the Disk ][ drive spindle to get the speed properly tuned. I was able to get a drive that would not boot working that way. It works!
Click to expand...
I don't think you are telling truth.
 
george said:
I don't think you are telling truth.
Click to expand...
My now working Disk ][ drive disagrees with you.

ldkraemer said:
Use a fluorescent light and the "stroboscopic" timing marks
Click to expand...
Even though the Shugart SA-400 adjustment instructions indicate fluorescent, I don't think I could get a CFL to work. Maybe how the new bulbs are made? Incandescent bulb in a dark room in a plug-in lamp close to the drive worked for me. I am sure cheap LED string lights would work too.
 
If your drives don't have the timing marks, or whatever they are called, you can get digital optical tachometers pretty cheaply. These frequently come with reflective disks/tape - like this one I don't have one so it is not a recommendation on any of them, but I have thought about getting one. I haven't needed one because the few drives that I have, either have the timing bands/and or will work with software that gives me the rpm.
 
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A specific model of CFL may actually be driven at a higher frequency than the AC line if it has a switching power supply in the base.
 
When it comes to inability to read other drive's disks for Apple ][ disk drives, speed is usually the issue. Alignment is rarely, if almost never, an issue. Of course, the most common issue with these drives overall is a dirty read/write head.

That is assuming you have an otherwise working drive. Non-functional Disk ][ drives have a few chips on the analog that commonly fail, are socketed, and relatively easily replaceable.

I've adjusted speed on a Disk ][ using a free strobe app I downloaded on my phone. It is generally easier to adjust the speed if you have a diagnostics disk that checks speed continuously (assuming you have a working Apple ][ and a second working drive), or access to an Applesauce device.

Commodore disk drives tend to have more issues with alignment, requiring alignment disks or a scope.
 
There are a couple ways. You need a florescent lamp that isn't one of the new ones. They use a high frequency and not 60 HZ, so CFL are not too good for this.
I suspect an incandescent lamp with a really thin filament might work but never tried it. Something like the lamps used for sowing machines or such might work.
Neon lights such as an NE2 will work with the appropriate series resistor ( careful with the high voltage and use appropriate insulation to protect you and the drive).
A LED light will work with a low voltage transformer and resistor. Do use care as some LEDs can be damaged with back voltage. Putting a parallel shunt diode across the LED should be enough to protect the LED or two LEDs in parallel will give the expected 120 HZ that the strobe disk like for higher contrast.
I could think of other ways but I think one gets the idea.
Dwight
 
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