I have or hopefully had the same problem: red light blinking on the charger and won't start charging. It was working fine while connectect to the 4-port external USB hub, but then suddenly it just stopped charging. So, I connected the wireless charger to another USB cable and charger, and S3 started charging normally. I also noticed the USB cable is not always connected properly to the charger. I am using now other than Samsung's original USB cable and wall charger (240V). I have the European version of S3 Frontier (SM-R760) sold in Finland, and I suppose it has the latest firmware/software inside that is available in EU/Finland (Tizen v18.104.22.168, software R760XXU2CQK3).
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