This is a note on Steppers from old DVD, after two days of struggle. Hope this will be of use to others.
The Internet is full of encouraging XY Plotters made with steppers from old DVDs and Arduino. Thought I will at least check the mechanism out.
To my dismay I discovered that the stepper shakes but never moves!
The bipolar stepper has two coils with resistance of 10.7 ohms. Which means, it will draw at least 0.45 mA DC per each coil when connected to 5 volts.
This is lot of current to go through the LM 293D IC. No wonder it gets hot and probably stops working.
I do not want to fix heat sink on a 16 pin IC. I wonder how quite a few people suggested direct LM 293D drive.
I went crazy trying all the combinations of step sequences, without minding the above facts.
In this video: Old DVD drive motors revisited - YouTube
the author described a way out to check simple sequence in a easy method.
I followed same method applying 5 volts to each coil. See enclosure - DVD Stepper Sequence.jpg.
My stepper moved successfully.
But to make it run with Arduino I need to buy a proper driver board.