Hi Everyone,
Thanks for ideas... I need to know the variations on this so I can help teachers be ready for servo problems...
Time to get the scope out, and monitor the 5volt supply when the servo is jittering.
I have ordered a complete servo testing device than can capture maximum currents. I will also do some bench testing tomorrow with metered power supply etc...
@Wawa good points about all the detractors in the chain... I DID have a situation with a poor USB cable once, and I will test for that..
Right now different schools and administrators are giving me lots of information that is often conflicting, like "Last years kits had servo problems, but we were OK the year before".. I'm trying to sort out the many variants in this. And NOW some schools are going to Chromebooks which is another variant.
Jeezum Crow (Vermontism) , LEDs and LCDs and Bluetooth modules and even stepper motors are not problems. Those simple little servos are the hassle.
OK, back to work...