My Pi 3 B+ suddenly stopped working while I was setting up a GPIO connection to an LED through a breadboard and it won't boot anymore. I formatted the SD card and put NOOBS 2.8 but it still won't boot. The red power LED is on but the yellow ACT LED does not blink. I don't get any display through the HDMI port.
I now have learned that I don't have a proper power supply. I used my phone charger but it's not a 2.5A as it should be. Is it a possible cause of this kind of issue? I had used this Pi a couple of times before with the same power supply and apparently it was working fine. It was giving me the thunderbolt sign from time to time though.
If I get a proper power supply, is there any chance for my Pi to work again? Is it possible that it's been permanently damaged by using an insufficient power supply?
Update
A friend of mine has a Pi 3 (not +) with a proper power supply.
- I tried his power supply with my Pi: still no boot and no ACT LED blinking
- I tried his SD card with my Pi: still no boot and no ACT LED blinking
- I tried my SD card with his Pi: it works fine
I've called customer service of the online store from which I purchased my Pi and they confirmed it looks like the Pi itself has a failure and I'm going to return it.