Chosen Solution
I took my iPhone 6 in for a charging port replacement as it was not charging. They replaced the charging dock assembly but when I got it back, the cellular phone and 3G data signal is substantially poorer than before. I do not get signal at all in places I used to get fine signal, and other places I got great signal I get very poor signal. I have lived and worked in the same area for 3 months and had consistent signal every day without change, only now after this repair it is suddenly substantially worse. I took it back to the shop and explained but they washed their hands of it and said there was no issue. On the iPhone 4 there were a number of metal tags that connected the cell antennae and if these weren’t connected fully it could degrade signal. What can I check on the iPhone 6 that could be responsible for degraded signal? I do get some signal in some places but it is much worse than before and it is definitely since they replaced the charging dock.
First of all, why did they replace charging port? It is actually quite rare to damage the iPhone lightning port, 80% of the time, it is just dirt, lint, fluff etc. Inside the port that prevents proper charging. As for signal, it’s possible if they replaced it that it may be a low quality part, or they haven’t connected everything up correctly. You could open it up and post some pictures here for me to have a look at, I could possibly help then. :-)