- Jul 28, 2013
- Jul 28, 2013
Hi, thanks for sticking with me on this. I appreciate your feedback. However, I've swapped the display console out with a known good one and the entire system works as expected.Clean the potentiometer track (squirt contact cleaner in or use a syringe and get some petroleum jelly in there).
If the system has a servo motor that isn't 'tracking' properly then you either have a bad drive to the motor or a bad feedback to the controller. Since the motor actually moves I'd go for a 'missing' (or intermittent) feedback signal.
It's also possible that the gearing between motor and feedback pot is missing tooth or two - this will also result in 'hunting'.
Because of that, I have eliminated the servo motor and potentiometer hardware as a cause of the fault and I'm isolating on the display console to trace the fault. I'm currently focusing on the motor driver IC chip and the feedback circuit. Your suggestion was to trace the feedback circuit from the motor to the microprocessor. That's where I'm at.
I'm trying to determine if the chip alone is the cause of the fault or if there are additional components that may be to blame. My thoughts are just to replace the chip and see what happens. The issue with that is the chip is a WT7901 and I can't find one. However, I have other consoles that use a similar chip BD6210 and I'm considering if I can substitute that chip and I'm looking for a pinout diagram and spec sheet to compare the two chips and see if they may be interchangeable.