Trackspot motors 'surging' / 'hesitating'

A little more info if it helps any, both of these are v1.9 boards but they have the updated 100pf/300k RC network on the 6219's, but I don't believe that is where the fault lies as both were modded at the same time and only one fixture has the issue (also both are running v4.2 firmware since they have the updated RC network).

The one with the problem you can feel the motor 'kick' if you put your finger on the color or gobo wheel while running in spin speed 1,2, or 3. So at face value it appears the 6219 is not getting proper information, like it's skipping a couple of bits of resolution. Still continuing to probe with my oscope to try to find the issue.

Just something to check. I had a similar, but more intense, problem on a Trackspot that hit my shop recently. It was only one of the motors, the gobo wheel motor, but it jumped around like crazy rather than moving in any particular direction. I went crazy probing the logic driving the latches, and the output of the motor controller chips. Finally, I noticed while disassembling the unit to try to replace that motor (thinking that it must be the motor) that the wires running to that motor had gotten pinched, by a previous reassembly, and were making intermittent contact. The wires were hidden in the little tunnel that protects them from the lamp heat, so I assumed they must have been OK, but it turns out that was the problem.

I'm not saying this IS your problem, but it's something to check.

Jeff.

Thanks, I think we finally nailed it down to motor/firmware incompatibility. All of my fixtures are running 4.2b firmware with the upgraded R/C networks, however, apparently that is not compatible with the original motors that don't have the quick disconnect on the side of the motor (soldered harness).

I was finally able to test this by taking two fixtures side by side and jumper the harnesses across to the other fixture with the newer motor and the rotation was smooth, no surging.

Im having this same problem with my gobo & color motors.....they just surge and bounce left & right then i get the error tone....any clues as to what would cause those motors to do that?

i have a few trackspots with 93,94 boards in them. their are no errors they work great but no one can seem to tell me why they are making a high frequency noise and no its not the error beep all the stepper motors are doing it but their is no issue with it in audio or dmx mode everything works.. to me it sounds like a bad diode or the rectifier .. they only make the noise in blackout mode or just at an idle it is like it has a bad power issue .. if anyone or anybody has had this problem?? could it be the voltage regulator ? its got to be something on the 24 volt rail ? need help please .. and yes they work with all the controllers fine even working with my elation or pc show express .. like i have said the units run and respond great to audio or controller it is just that high frequency noise they have ..

They made a change in later version to a different R/C network and upgraded the EPROM which as I recall makes the stepper motors operate at a higher frequency which is less audible. The work is quite intensive to change the components and then you need an EPROM eraser and programmer to re-flash the EPROMS