QUESTION: 8" drive spindle motor repair or change

[enrico]

I have a couple of 8" drives Mitsubishi M2863 slim type that I recovered I think around 1990 total in excellent
conditions with which I created images and written several floppy disks 8". For some reason, including my
incompetence, both their spindle motor do not run any more. And powering correctly with only +24Vdc the circuit
part of the engine rotation control of the disk (called spindle motor) begins to smoke near a chip LB1620. The
schematic contained in the maintenance manual of the drive includes components of other different model of
splindle motor circuit. If that were possible, how could I be able to run the disc correctly: reusing partly
engine or even replacing it with analogous maybe even creating handcrafted a motor with pieces of recovery and
manage the number of revolutions possibly with special circuit or with arduino?


Pics
https://www.dropbox.com/sh/p12w71v69tjgfz7/AAAIReql4Se5ZCkLClPoAVOPa?dl=0


references
M2896-63_Maintenance_Manual
https://www.dropbox.com/s/8rhukkr1xf78m8c/M2896-63_Maintenance_Manual.pdf?dl=0
M2896-63_Half-Height_Drive_Brochure
https://www.dropbox.com/s/elmj3nwz59dz2eo/M2896-63_Half-Height_Drive_Brochure.pdf?dl=0


Spindle motor SRC SHINANO TOKKI CORP. MADE IN JAPAN 702V
Modello DLF-3ME DC24V


Any suggestion is welcome.


Enrico

 

[NeXT]

May sound dumb, but try recapping the board. If the capacitance and filtering drifts off the controller basically malfunctions and doesn't toggle coils like it should. I've caught it now on a 5.25" and 3.5" drive but nothing says it wouldn't try to happen on an 8" drive, especially if both mysteriously die in storage.

 

[Chuck(G)]

There's no certainty that the motor itself is bad. What happens if you temporarily remove the driver transistors (Q4, Q5, Q6) that are connected to the +24V line? When you apply power, does the board still smoke? If it does, then it's not the motor, but some (yes, it could be a cap) other component on the board. The Mitsubishi uses a 3-phase PM motor; it's unlikely that it's bad.

 

[tipc]

what does it smell like? Capacitor smell is very distinctive, would smell very different from the smell of smoldering copper and varnish (and a bit of iron I guess). A burning ic . . . it's been too long since I smelled that (usually they don't smell much anyway).