Chosen Solution

After finding a used iPhone for cheap I thought it would be a good idea to replace the backing plate on my iPhone 5s after watching hours of tear down videos and successfuly attempting a tear down and re install on a broken iPhone I went through with the replacement but after swapping every thing out and installing it in the new case I noticed it acting funny calls came through just fine but my data kept jumping around and when I placed a call it jumped down to 4g which is something it never used to do after noticing it heating up more then usual and my signal being weaker then usual (my brother has the same phone with the same service and side by side I have 2 less bars and it jumps down from lte to 4 g a lot also loses service) after a lot of trouble shooting and trial and error re installing of the lighting port I must have taken it apart 8-9 time by now I gave up and reinstalled every thing in the old case. But the problems didn’t go away and I just discovered the mophie case I have been using for the last six months no longer works when ever I slide it on, my iPhone loses all signal?? I’ve tryed every possible trouble shooting techniques and i’m out of luck things I’ve done tryed a new lightning connection tryed a new speaker and antenna watched 3days worth of YouTube video tryed every combination of old shell new shell checked every screw for good connection i have all the tiny little washers and spacers you’re not supposed to lose Things I haven’t tryed spiking my iPhone in the floor please help

Did this used iPhone ever work properly? That’s not really clear in your otherwise detailed description. Replacement phone housings can be touch and go. Some work perfectly, others have all kinds of antenna issues. The housing is the antenna and all of those wires and interconnects etc. are just there to get the signal to the RF part of the logic board. When you moved everything back to the original housing (of the used device?) you now had the same issue? This is why it’s important to know if the phone worked fine before all of this. If it didn’t (or you didn’t test it), then the problem may be logic board related. If it did work fine, then either you have a poor quality replacement housing or you did something wrong. Using the proper length screws in the right place is important (and critical for the screen bracket) and keeping track of tiny washers and the proper order of all the bits.