[Ether]

Originally Posted by fmercier

Thanks for all the comments.
We have reset the Spark. LED still has intermittent blinking in reverse. The actual motor speed is slow, matching the low output signal. Per our program, we are sending a value "1" for forward and "-1" for reverse. The result is the same with a second Spark. We have also tried a jaguar, and the drop off is less, but there is still a clear difference between forward and reverse. ???

Do you have, or can you borrow, a DVM to measure the PWM signal at the Spark's PWM input terminals when you are commanding forward and reverse? See posts 9 and 10 below.