On 2017-Dec-09, at 6:06 PM, allison via cctalk wrote: > On 12/09/2017 07:52 PM, Fred Cisin via cctalk wrote: >> On Sat, 9 Dec 2017, allison via cctalk wrote: >>> I have several Epson PX-8s and i used them.. They work well with the >>> various wedges I have. >>> I also Have a PF-10 which is the portable 3.5" 40 track two side floppy. >>> The problem is it randomly does not turn the media unless I give it a >>> push to get it turning. >>> Things checked: >>> * Batteries, NEW fully charge (Both). >>> * internal Power supplies, current voltage and bridged with external >>> supplies does not help. >>> * media checked for binding, it does not. >>> When it turns it reads and writes correctly and at the correct speed. >>> It may do so without help for many tries then will stop required a >>> manual push. >>> At first glance I though there were motor bearing issues but have >>> verified >>> this is not so. If I force motor on and restrain it I has good torque >>> and no >>> dead spots. All signals in the motor control look good on the scope. >>> Any thoughts? >> >> How does it detect the presence of a disk? and/or disk change? >> >> > Functions normally save for the motor does not always turn on command > but will if manually pushed. All other functions are normal.
How about a problem with the current supply to the motor, such as low gain in the driver. A progressive failure may be just on the edge of supplying enough current to keep it rotating, but not enough for startup torque.
