I have two slim 5.25" drives. One is from a Laser 128, the other is a Maple drive. They both seem to basically work (drive spins, light comes on) but the stepper motor doesn't move the head. When off, I can manually move the heads without issue.
On the Laser drive, if I slide the head back to track 0, Copy2Plus can verify track 0 but then cannot advance the head for the rest of the tracks. The Maple drive's head can also move but I can't get it to read track 0. Maybe that head is dead.
From the Disk II schematics, it appears the ULN2003 drives the stepper motor. With an oscope, I can see activity on the 4 channels of output on that chip but haven't replaced it yet. The Disk II schematics also seem to make it look like the stepper motor signal flows from the controller to the 2003 right to the motor. It would be nice to find schematics for the Laser and Maple drives since the layout seems a bit different.
Would a good course of action be to try and replace the uln2003? Maybe both stepper motors are bad? Is there a good way to test the stepper motors? I tried searching for the motor on the Laser drive and google didn't return anything.
Just curious if anyone else ran into similar drive issues such as this.