Hello.
I just finished repair of Tandon TM50-2 floppy drive and have question.
The drive was purchased as unknown condition and main initial issue was open upper RW head. But I was extremely lucky to be able to solder the wire breakage in the head.
I did "upgrade" that allows to adjust spindle motor belt tension. The upgrade shown by me here.
Initially looks that the drive works without problem but later I payed attention that 10-15 min of powering the drive, stepper motor starting to loose steps. As well it became pretty hot, I guess something like 50-60 C. Initially I thought that something is wrong with stepper drive electronics that causing to wrong stepper phase timing that lead to skip of steps and worm up. Schematic analyze and measurements with logic analyzer and scope showed next picture. Single Step command from external floppy controller causing to stepper motor control circuit move stepper motor by 2 steps and phase pulse to the motor during one of the steps was very short. Length of the pulse defined by RC circuit, when schematic refer to RC values for "Slow" and "Fast" stepper motors, don't know which one installed in my drive. Incremented R value caused to increment length of the phase pulse and totally eliminate loosing steps problem. But stepper motor still warms up, furthermore if I understand correct its schematic there is current through one of the phases at any point of time, that probably heat up the motor.
So I wrote this long story just in order to ask, if someone use Tandon TM50 drive. Just for curiosity check stepper motor temperature 15 minutes after power on.
I just finished repair of Tandon TM50-2 floppy drive and have question.
The drive was purchased as unknown condition and main initial issue was open upper RW head. But I was extremely lucky to be able to solder the wire breakage in the head.
I did "upgrade" that allows to adjust spindle motor belt tension. The upgrade shown by me here.
Initially looks that the drive works without problem but later I payed attention that 10-15 min of powering the drive, stepper motor starting to loose steps. As well it became pretty hot, I guess something like 50-60 C. Initially I thought that something is wrong with stepper drive electronics that causing to wrong stepper phase timing that lead to skip of steps and worm up. Schematic analyze and measurements with logic analyzer and scope showed next picture. Single Step command from external floppy controller causing to stepper motor control circuit move stepper motor by 2 steps and phase pulse to the motor during one of the steps was very short. Length of the pulse defined by RC circuit, when schematic refer to RC values for "Slow" and "Fast" stepper motors, don't know which one installed in my drive. Incremented R value caused to increment length of the phase pulse and totally eliminate loosing steps problem. But stepper motor still warms up, furthermore if I understand correct its schematic there is current through one of the phases at any point of time, that probably heat up the motor.
So I wrote this long story just in order to ask, if someone use Tandon TM50 drive. Just for curiosity check stepper motor temperature 15 minutes after power on.