The washer you found is likely placed behind one of the screws on the actual dock itself. I think... If you're not getting signal after doing this repair, I would look into the cable that connects the Lightning dock to the logic board. It's possible that even if the part is connected, it may not be doing its job
[product|IF124-010]
Beyond this, you could try toggling airplane mode off and on, or doing a force restart. Also I'm hoping you disconnected the battery, prior to doing the repair
The washer you found is likely placed behind one of the screws on the actual dock itself. I think... If you're not getting signal after doing this repair, I would look into the cable that connects the Lightning dock to the logic board. It's possible that even if the part is connected, it may not be doing its job
[product|IF124-010]
Beyond this, you could try toggling airplane mode off and on, or doing a force restart. Also I'm hoping you disconnected the battery, prior to doing the repair