Duct tape -- it can fix anything. 
Okay, with that out of the way ...
Roku only supplies the operating system for a "Roku TV". Hardware issues needs to be referred to the manufacturer of the set.
Roku TV Manufacturer Support Contacts:
https://community.roku.com/t5/Manufacturer-Support-Warranty-Resources/Contacting-Support-for-Your-Ro...
If you want to "do it yourself" a YouTube search for your TV model (or at least its manufacturer) may be your best bet for instruction. Try "replace [brand name] coaxial connector" or "replace [brand name] antenna connector".
- Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
- Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T
- TCL Roku TV 43S425/C107X, Ser X000001R60KV, wifi