Fried another two programmers :-(

Other Hardware 3rd Party Boards
7

jwatte:

CrossRoads:
Post a schematic - I didn't see any mention of diodes across the motors.

Thanks for the suggestion! It's an H-bridge going both ways -- I can't really use diodes there.
The N-channel MOSFETs (high and low -- driven by IRS2301 drivers) have built-in body diodes that go the way they can go.

Picture the diodes as a full-wave bridge -- with the commoned cathodes connected to +V, the commoned anodes to Ground, and each electrode of the motor connected to one of the cathode-anode junctions (where the AC would go in, in a power supply.)

Those "body diodes" aren't acceptable as flyback diodes (I say, "No Way!")

          • Or keep your motor unpowered till after you unplug your programmer.
            I can sketch out the diode arrangement, if necessary.