HI All,
I have a UR5 CB3 that refuses to boot up. The screen comes alive for a second when the power button is pressed on the pendant but the 48v relays never trigger.
I popped it open and traced the lines. Everything to the Power Distribution board is plugged in correctly and has continuity. When I initiate the start sequence I can see that I have +12v on each relay pin between that and ground but the pin on the other side of each relay coil is also +12v. Of course after a few seconds of waiting for 48v the system shuts down as correct power was never received.
So the "Conn." cable that connects the Safety Board is 4 wires.
- Ground
- relay 1
- relay 2
- and a 4th that is connected to the other side of the relay coils. (should be ground?)
Presumably this 4th pin would also need to be ground in order for the contactors to close and I'm not sure why I would be getting +12 v between pins 1 and 4 and of course 0v between 2/4 and 3/4. Any idea why the safety board would behave like this? Maybe I'm just missing a jumper somewhere and it's a safety feature that has been triggered?
A few notes:
- both relays are good/tested.
- both power supplies are good/tested.
Thanks!
