Measure spindle speed Tandon TM100

[NicolasF]

I've been trying to measure the spindle speed of my Tandon TM100 floppy drive using programs like AlignIT and Speed but both programs are giving me errors saying that the speed is out of bounds or that there is a IO error.
I presume that if both programs cannot measure the speed is because there is some problem with the part of the drive that is used to measure the speed.

So... the question is:

What part of the floppy drive is used to measure the spindle speed?

I guess it's either the read heads or the index sensor or both maybe??

 

[Chuck(G)]

The traditional way to get spindle speed right is to use a line-powered strobe light (a neon lamp, old-style (iron ballast) fluorescent, or best, an LED night light) and the strobe disc that's glued to the spindle flywheel (If you've lost the strobe disc because of the glue drying out, you can make one). Adjust speed until the strobe bars appear to stand still.

No computer necessary--just ground the MOTOR line.

The problem with software approaches is that they're overly sensitive to ISV (instantaneous speed variation) and can only calculate the time it takes for a complete revolution. A low-tech strobe disc is far more accurate--and much quicker to get right.

You didn't say which TM100 that you're using. The TM100-2/2A/4/4A are 300 RPM drives, the TM100-4M is a 360 RPM 100 tpi drive.

 

[NicolasF]

Yes, the only way I have to check the speed is by using the fluorescent light.

But why I can't use any software to check the speed??

The drive is a TM-100-2A.

 

[ruthlessperson]

Hello There There is no feedback sensor on the drive that I know of, it's something that is done manually with a light like Chuck said and there is a speed control screw on the rear of the drive the long narrow thing with screw on top on the small PCB. Thanks and have a nice day!

 

[MikeS]

You didn't say which TM100 that you're using. The TM100-2/2A/4/4A are 300 RPM drives, the TM100-4M is a 360 RPM 100 tpi drive.

I should learn; every time I argue with you it turns out that you're right and I'm wrong, but are you sure? That's the first time I've heard of a 360RPM TM100; The docs I have say they're all 300:

-1: 48TPI/SS
-2: 48TPI/DS
-3: 96TPI/SS
-4: 96TPI/DS
3M: 100TPI/SS
4M: 100TPI/DS

But all at 300RPM; do you have a reference that says otherwise?

mike

 

[NicolasF]

Hello There There is no feedback sensor on the drive that I know of, it's something that is done manually with a light like Chuck said and there is a speed control screw on the rear of the drive the long narrow thing with screw on top on the small PCB. Thanks and have a nice day!

There are 2 ways of measuring the spindle speed, one is using the pattern bar located on the wheel of the spindle and the other way is by using a program.

I can check the speed by using a fluorescent light and the 50 Hz pattern but I can't do it using a software, so... my guess is that there must be some kind of problem in the electronics of the drive.

 

[MikeS]

I've been trying to measure the spindle speed of my Tandon TM100 floppy drive using programs like AlignIT and Speed but both programs are giving me errors saying that the speed is out of bounds or that there is a IO error.
I presume that if both programs cannot measure the speed is because there is some problem with the part of the drive that is used to measure the speed.

So... the question is:

What part of the floppy drive is used to measure the spindle speed?

I guess it's either the read heads or the index sensor or both maybe??

Is the speed correct with the strobe disk? I don't know about those particular tools; some I've used definitely use the index sensor since they can test a blank disk. Try testing the speed of a completely blank (bulk-erased) disk on a known good drive.

Or just use the strobe disk; universal and very accurate.

As to your particular drive, do you have any means of checking whether you're getting any index pulses on pin 8? Don't forget that it has to be pulled up to 5V if it's disconnected from the controller.

 

[Chuck(G)]

Ya got me, Mike! It is indeed 300 RPM. Probably a bit of errant french toast from breakfast gumming up the works.

5.25" 1.2MB drives spin (at least in 1.2MB mode) at 360, as do 8" drives and "tri-mode" 3.5" (1.23MB) drives. Maybe it was the 77 track-ed-ness of the 4M that caused the mental burp...

 

[Chuck(G)]

You can use software to check the speed of the drive, if you have a controller that conveys the state of the index line (765-type ones don't, but many WD17xx do). If your drive can read a floppy, you can simply time the interval it takes to read the same sector repeatedly. Or you can connect a bench counter/timer to the index pin of the drive.

But none of those is as simple and accurate as the strobe disc method.