Ned,
I went ahead and supplied 5 volts to the encoder and followed your
instructions for scope use. I could watch the transitions on the
screen. Thanks. If the carriage is moved back and forth .0002 the
transition will show. Still, the mysterious backlash seems to be
present. Small movements seem OK but not large ones. It's hard to
count transitions on the screen and watch the indicator too. I got
someone to count the transitions on the screen while I watched the
indicator. BTW, the indicator is OK, it doesn't have bachlash. Still,
I can't see if the shaft is moving or not. So the laser is probably
next. However, I think the problem is hysteresis in the rubber belt
driving the encoder from the carriage. We'll see.
Eric