Robots that were manufactured before 2019-09-05 need a hardware adjustment before you can attach GEN2 pipettes to them.
Your OT-2 controls pipettes through white ribbon cables: the pipette mount connection ribbons. But on these older OT-2s, they're not long enough to comfortably reach the connectors on GEN2 pipettes.
This guide will show you how to lengthen the pipette mount connection ribbons, so you can use your older OT-2 with GEN2 pipettes.
Check if your OT-2 needs this adjustment
Check when your OT-2 was manufactured by reading its serial number.
If it was manufactured before 2019-09-05, it does need this adjustment. (Unless someone else has already done it.)
Otherwise, it shouldn't need this adjustment. Attach pipettes normally, or reach out to Opentrons Support if you're having trouble.
If you're having trouble figuring out whether your OT-2 needs this adjustment, please contact the Opentrons Support team for further assistance.
Remove all pipettes from the robot mounts.
In the Opentrons App, select Pipettes & Modules underneath the connected robot’s name. Select Attach on the left pipette mount. (Later, you'll repeat this process for the right mount, as well). The left mount will lower at the front of the robot.
Power the robot off via the switch on the side of the robot.
With the left mount lowered, pull it down to make sure that the pipette mount connection ribbons are exposed
Adjust the pipette mount connection ribbon
Remove the pipette connector from the plastic enclosure. It helps to pull down on the bottom "tooth" of the enclosure with one hand while removing the connector with the other.
Remove the connector ribbon from the plastic casing. It may help to use a screwdriver to assist in removing the ribbon from its casing.
Place the pipette connector back in the plastic enclosure so that there is enough slack for the ribbon to reach the GEN2 pipette. Rewire the connector ribbon through the plastic casing.
Attach the GEN2 pipette to ensure the pipette connector reaches the pins of the pipette. If the connector does not reach the pins, redo the previous 3 steps above so that there is enough slack for the ribbon to reach the pins.
Once you have confirmed that the GEN2 pipette can be attached, the process above will need to be repeated for the right mount.
Please contact the Opentrons Support team for further assistance.