Hi all!!! This machine randomly keeps dropping RPM. Sometimes just for a brief moment. and sometimes RPM stay down. It happens like this: Machine is hammering at approx. 1800RPM, RPM dial is for example (don't know exact notch) in notch 6. All of a sudden governor motor arm moves and drops RPM to approx. 1000 RPM, and just stays there. Screen shows correct RPM in both 1800 and 1000 RPM. There is no alarm or fault created. Voltage from RPM dial to computer stays the same. If I move speed dial from notch 6 to notch 7, RPM increase. But not to 1800+, but it starts from 1000. Like notch 6 becomes 1000 RPM. To make everything normal again, speed dial needs to be moved to zero notch, and then back up. It looks like governor step motor looses it's position somehow. But how come there is no alarms? Computer should know that notch 6, shouldn't be 1000 RPM, but about 1800? Doesn't it monitor RPM this way? What do you think? Maybe bad connection to governor motor? But it should create alarm if that is the cease, right? Did anyone ever have a problem like this? Thanks!!!
Either your stepper motor position sensor circuit is failing or you have too much play in the fuel linkage and it's causing the stepper motor to hit the internal stop. You can temporarily fix this issue by doing an A adjustment but you will more than likely have to replace the stepper motor.
Hi! No play in linkage, nice and tight. There is no sensor for step motor position, except just contact for "home" position. What suprises me that machine doesn't react at more than 800 RPM difference between actual and expected RPM.
So what you’re saying is the computer is losing its home position. That would indicate a problem with the sensor or whatever is the home post.