Chosen Solution
Just received and changed the battery in iPhone 6. Now phone is overheating . We noticed that there might be a damaged/ missing pin on the board in the phone. Not sure if that is the cause or how to fix. We do have another iPhone 6 minus the battery and a non working antenna for parts. Update (05/19/2020)
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Where exactly are the pins missing? And where did you buy your battery from? Excess heat is typically a sign of a short.
I would try another battery. How good of quality was the battery? I couldn’t see any pins bent or missing in the picture. You should also clean the battery connections with a qtip and alcohol, make sure to dry it before hooking it back up. If the connection is bad it can cause resistance and heat.
