• Please review our updated Terms and Rules here

CP/M 2.2 - Single Floppy Operation

MarsMan2020 said:
Something is up with the stepper motor, it does not spin as freely as the working drive with the belt removed & won't spin up the drive with the belt on.
Click to expand...

I'm not really familiar with the Vector MZ, but a floppy drive is a floppy drive. Actually 8" floppy disks are floppies. 5.25" disks are technically mini-floppies.

The stepper motor is usually what the motor that moves the head assembly is called. The motor that powers the spindle that turns the disk is usually referred to as the spindle motor.

You have Tandon full height 5.25 mini-floppy disk drives, Right? Is that a TM-100-2 (40-track, double-sided) drive? This was a very common drive at one time (used by IBM in the original IBM PC, and by Radio Shack in the Model I and Model III).

And you say that one is not working and it appears to be related to the spindle motor, which is not coming up to speed with a disk inserted (motor does not appear to turn as freely as it should with the belt removed), I do I have that right so far?

Did you verify that the motor is not coming up to speed by checking the speed strobe label on the bottom of the spindle pulley (shine a fluorescent light on it)? Did you try adjusting the speed by turning the control/trimmer on the speed control board (the small board stuck on the rear of the drive chassis).

On the Tandon 5.25 full height drives, the spindle motor is one of the more reliable parts. It should spin freely, if you spin the motor pulley a spin with your fingers. While speed control circuit board is usually what fails in the spindle drive group, motors do sometimes fail (shaft is usually harder to turn or seized on a failed spindle motor).

Fortunately, the are lots of dead Tandons full height 5.25" drives floating around out there that you can scavenge the spindle motor off, and the motors are really easy to remove and replace. Many of the parts on the Tandon TM-100 Series (MT-100-1, 100-2, 100-3, and 100-4) full height drives are interchangeable. Changing the spindle motor does not require a visit to the shop for head alignment afterwards. Just look for a donor drive that connects the motor (same way that your drive does) to the speed control board (there are a couple of different designs for the speed control boards and they use different connectors). Cut the cable ties holding the wires in a bundle, R & R the screws that hold the motor in place, and swap the motor. Use the better belt from the two drives when you put the thing back together. After assembly, verify motor speed using the strobe label on the bottom of the drive and adjust as necessary on the speed board.
 
I've got several of the 1016 drives. 100 tpi (not 96) drives all (mine are double-sided). The seek time is pretty slow--about 30 msec. track-to-track, since these drives use a leadscrew positioner with something like 4 steps per cylinder. Very accurate, but Micropolis was making precision leadscrew positioner floppies when the rest of the world had moved to much sloppier positioning. Slow 8" drives operate at better than 15 msec. track-to-track. And note the head-load/settle time--75 msec.!

The spindle motor is a simple DC brushed job, so failing mechanical damage, you may be able to free things up by re-oiling the bearings with some WD-40 or better, a light oil. The shaft should free up eventually, assuming that rust hasn't invaded the innards.

Whatever, if you've got the 100 tpi drives, don't toss them--Micropolis drives were the best of their day and quite expensive. 100 tpi floppy drives are pretty rare. If you've got the 48 tpi version, save it for parts--but for the positioner leadscrew, most of the rest of the same parts were used on the 100 tpi versions.

And pay attention to the connector pinout. Close, but not exactly the Shugart standard. For example, DS4 is on pin 34, while READY is pin 6.
 
Last edited:
Chuck(G) said:
I've got several of the 1016 drives. 100 tpi (not 96) drives all (mine are double-sided). The seek time is pretty slow--about 30 msec. track-to-track, since these drives use a leadscrew positioner with something like 4 steps per cylinder. Very accurate, but Micropolis was making precision leadscrew positioner floppies when the rest of the world had moved to much sloppier positioning. Slow 8" drives operate at better than 15 msec. track-to-track. And note the head-load/settle time--75 msec.!

The spindle motor is a simple DC brushed job, so failing mechanical damage, you may be able to free things up by re-oiling the bearings with some WD-40 or better, a light oil. The shaft should free up eventually, assuming that rust hasn't invaded the innards.

Whatever, if you've got the 100 tpi drives, don't toss them--Micropolis drives were the best of their day and quite expensive. 100 tpi floppy drives are pretty rare. If you've got the 48 tpi version, save it for parts--but for the positioner leadscrew, most of the rest of the same parts were used on the 100 tpi versions.

And pay attention to the connector pinout. Close, but not exactly the Shugart standard. For example, DS4 is on pin 34, while READY is pin 6.
Click to expand...

They are indeed the 100 TPI version.
 
You must log in or register to reply here.
Back
Top