Im getting an error for wrist 2.  It is C39A5 Logic and Termporal Monitoring Fault:  Too fast state change.

We just had a UR3 with the same fault on wrist 3, we also saw that we were getting C70 errors which is gear box near shear limit. We had to replace the joint as it had failed. 

Have you tried following the cold reboot procedure as prescribed in the service manual?  

No I have not tried that yet.  The motor was hot when the tech got to it last night so it sounds like there is a good chance it is the same issue.  I was thinking maybe a problem with the brake staying engaged but it looks like there is grease running out from the joint that was hot. 

The brake solenoids are all working properly and if I manually move the joints after releasing the brakes for any joint then the encoders pick up the movements so I would say the encoders are good.  I also tried maxing the payload just to see if the motor could power thru the point it is sticking and it still will not move. 

We had a gear box shear a tooth once that caused it to lock up at a certain point, could not move the joint even manually past that point. 

I finally got it running yesterday.  I cleaned the encoder up good then worked the joint thru its motion in manual several times.  The joint still feels like it has more resistance than the other when moving.  It sounds like I could have the same issue with the gearbox and I'm probably on borrowed time.  This is the only UR robot in our plant so I don't have any spare parts as we normally use Epson.  I'm going to get some spares on order.  How hard are these to switch out? 

UR3’s are pretty easy to do. Takes less than 30 minutes. Challenge can be that critical waypoints will need to be cleaned up some.  How old is the robot?

2016

Oh ok.

Thank you for the help.  I will update later.