Sonnet Echo Express III-D Thunderbolt 3 Edition User Manual page 14

Appendix A – BNC Connector Installation Steps
6. Grasping the Thunderbolt interface card by its edges, insert the card
back into the inner assembly (Figure A-4).
7. Line up the card's connector with the slot, and then gently but firmly
press the card straight into the slot; do not rock the card or force the
card into the slot. If you encounter excessive resistance, check the
card's connector and the slot for damage, and then try inserting the
card again (Figure A-5).
8. Using the two screws you removed previously, secure the Thunderbolt
interface card to the inner assembly; do not overtighten the screws
(Figure A-5).
9. Return to step 11 on page 5 to complete the PCIe card and chassis
setup steps.
B
Figure A-4
Figure A-5