I've Raspberry Pi 3 b+ which is 2 years old since I purchased it. Recently, it has started behaving very strangely. I've installed a new rated power supply (5V 2A) for Pi board. The board runs fine for couple of hours without any over/low voltage complaints, but after awhile it turns off completely. When I tried to boot it again, only red and green light were on without any blinking. According to various forums, most of them said my SD card is faulty I've checked my SD card several times reflashed it with new a image. Still, it doesn't boot. Following this issue, I kept my Pi board off for 2 days, and when I last tried it successfully booted with no loss of data. But after 45 mins, it again started behaving as described earlier. In such a condition, neither display or Ethernet ports are responding. I'm not doing and heavy task Pi just running a FTP server. I've even installed heat sink plus 5V fan(being powered through GPIO pins of board)
UPDATE: I've kept my pi off for 2 days and then powered with last hope it's rated power supply but without the heatsink fan. It has been working fine for almost 6+ hours with old SD card. I think the fan which I had connected to pi on +5V & GND is not supposed to be done that way. Due to such faulty connection the polyfuse blows up and take hours/days or may be week to get rewired. I got this to know by visiting various forums. More if you know on comment below.
