Have successfully changed the motherboard on my xperia Z. Then recently the phone would only charge from a dead battery and if I interrupted the charging (ie unplugged and replugged the power supply) it wouldn’t continue to charge. Have just changed the battery from my spare phone now and I plug the power in, the red light comes on for about 10 seconds and then goes off. It’s not charging. Opened it up again and rechecked everything was ok, but still not charging. The old battery back in the spare phone is charging well and continues to charge when power turned off and on again. Was it not a defective/worn battery in the first place? What else could it be?
FYI I am using the same USB plug and cable for both.
I found this white adhesive tape just wrapped around the battery, so didn’t need to be removed