The last time I used the tablet was about 4 years ago. Needless to say, the battery was completely drained. I plugged it into a charging cable connected to an iPhone 2.1A charger but the display just kept on flashing. Hmm. I then connected it to a wall charger with the same result. I was 100% convinced it had to do with the power supply not being strong enough. The 2.1A output may not be true 2.1A. I then switched to a portable battery charger with 5V 2.1A output and voila, the Samsung Tablet is now charging as it should. The display stopped flashing, and it shows a battery with a small green line at the bottom indicating it is charging.