Created Date: February 22nd, 2019.

Examples are valid for:
CB3: Joint encoder PCBs in joints/robot arms produced after 20/06/2017 & prior to 01/06/2019:

UR3: 2017332530 to 2019330560

UR5: 2017355420 to 2019350990

UR10: 2017305210 to 2019301020

 

Corrective action from Universal Robots

• Since June 2019, the coating used for all PCB's have been changed to another and thinner dilution, that are tested to not cause any issues. 

 

Description of error:

The coating of PCB for the joint encoder has a variation in layer thickness. When connectors are mated, coating is sometimes not scraped off properly.

This can lead to reduction of power supplied to joint encoder, which will lead to joint encoder failures (C75 xxx)

    
This was found on Joint encoder PCBs in joints/robot arms produced after 20/06-2017.
See production date on Identification sticker on the Robot Arm.

 

Corrective action when C75 is seen:

Follow video or this guide.

Video can be found below as attachment.

Summary of video/guide

• Power down robot completely, see first 3 steps of Complete rebooting sequence in Service Manual.

Ensure EDS instructions from Service Manual are followed before taking next step.

• Remove blue lid.
• Unplug the connector from Joint encoder PCB. (Note: Not possible on size 0)
• Plugin the connector onto Joint encoder PCB. (Note: Not possible on size 0)
• Mount blue lid.
• Power on robot and test.

If the error does not disappear after this action, the joint need to be replaced.

 

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General

 See Service manual for more info about handling of ESD sensitive parts.

Tools needed:

• ESD wristband
• Two small flathead screwdrivers
• 45degree tweezer
• Extraction tool - DIP/IC tweezer

We recommend using an extraction tool when possible – DIP/IC tweezer to remove the connector.

When removing connector, only apply pressure to the connectors sides as shown above, to prevent damaging any parts.

 

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Before starting

Complete shutdown sequence.

 

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Remove cable with extraction tool – Recommend method

This method only possible on joint size 1 and 3 and is performed the same way.

Grab the connectors sides with the tool.

Now “pull” out the connector from the socket.

Then “push” the connector back in place, you can feel when the connector can’t go further into the socket.

If you listen closely, you can hear a click sound as well.

Repeat step 1 to 4 one more time if necessary, to ensure a good connection.

 

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REMOVE CABLE WITHOUT EXTRACTION TOOL

 

Size 0

It won’t be possible to perform this operation on joint size 0.

 

Size 1

Place you fingers, like on picture 2.

Now “pull” down until the connector is free from the socket.

Then “push” the connector back in place, you can feel when the connector can’t go further into the socket. If you listen closely, you can hear a click sound as well.

Repeat step 2 to 6 one more time if necessary, to ensure a good connection.

 

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Size 2 – Old encoder bracket 

On size 2, specially the one with the old encoder bracket.

It can be tricky to remove the connector. Use 2 small flathead screwdrivers and place them on the connector’s sides.

With the two screwdrivers pull out the connector carefully.
Before next step, be sure that the connector is aligned with the socket, like on picture 4.

Now gently push the connector back in place, by pushing on the connector’s sides.

You can feel when the connector can’t go further into the socket. If you listen closely, you can hear a click sound as well.
Repeat step 2 to 5 one more time if necessary, to ensure a good connection.

 

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Size 2 – New encoder bracket

On size 2, it can be tricky to remove the connector.

Use 2 small flathead screwdrivers and place them on the connector’s sides.

With the two screwdrivers pull out the connector carefully.

Use a tweezer to align the connector with the socket, like on the left picture above.

Then grab the connector on the backside, like on picture 5. Be careful not to damage the cable.

Now gently push the connector back in place, you can feel when the connector can’t go further into the socket. If you listen closely, you can hear a click sound as well.

Repeat step 2 to 7 one more time if necessary, to ensure a good connection.

 

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Size 3

Place you fingers like on picture 2.

Now “pull” down, until the connector is free from the socket.

Then “push” the connector back in place, you can feel when the connector can’t go further into the socket. If you listen closely, you can hear a click sound as well.
Repeat step 2 to 4 one more time if necessary, to ensure a good connection.

 

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Size 4

Like on size 2, it can be tricky to remove the connector. Use 2 small flathead screwdrivers and place them on the connector’s sides.

With the two screwdrivers, pull out the connector from the socket carefully.

Before processing till next step, be sure that the connector is aligned with the socket, like on the right picture above.

Then “push” the connector back in place, you can feel when the connector can’t go further into the socket. If you listen closely, you can hear a click sound as well.
Repeat step 2 to 6 one more time if necessary, to ensure a good connection.

 

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Testing

When the operation has been performed on the desired joint. Install the blue lid back on the joint, remember the correct torque for the lids screws 0.4Nm, connect the robot to the control box and power it on.
Power on the robot and move the joint in free drive mode, first 360-degrees one way and then 360 the other.

If the joint still fails, try redo the process again, or replace the joint.