TESTING RESOLVERS

To validate if you have a resolver problem, you will need to do a quick check to see if it has a pulse at all, then possibly remove it to do a physical check on the health of the bearings.
First, let's check its pulse.

The photo above shows how to check a resolver while the power is on and servos are energized.  Remove the bullet connector at J2 on the controller card(bottom socket on the controller board) and use a multi-meter in AC voltage mode to measure the voltage. It must read approximately 1.7VAC. If not, you either have a bad resolver, a cable unplugged from the resolver board in the motor, or a bad wiring harness. Your machine will not run until you resolve this issue.

If you have good voltage, you will need to remove it and do aphysical check. Photo #2 shows how to check a resolver shaft. Spinit and make sure it spins freely and very smoothly. If it is rough, replace it. Then check end play. Check side to side and in and out.
You should have not much more than about .002" play in any direction, and new resolvers have zero noticeable play.

A noisy or rough shaft or excessive end play will scramble the sine wave signals it outputs for position and velocity information to the controller card, thus bad finishes or simply motor overload faults as the controller card and amplifier cannot keep up with the random
spikes output from the resolver.

CNCPros.com offers both new and remanufactured resolvers under the part numbers ENC-0008 (new) and ENC-0008R (remanufactured). We highly recommend you purchase a spare for your machine. They are a higher failure rate item and having one in the cabinet for emergencies is worth its weight in gold.