HP Prime Bricked

[in06khattab]

Hi,

At the beginning of the exam today I was trying to reset my calculator and clear its memory. I usually press OK+SYM+HELP, the calculator restarted, but did not give me the memory clear message, so I tried it again. But still it didn't look like it was working, so while it was booting I pressed ON+APPS+ESC to see if that would clear it. But then the calculator screen appeared white for a second then remained black for the rest of the exam and still won't turn on.

I have tried resetting it by using a pin, pressing F+C+O, and pressing symb and all available methods online but the screen wont turn on. The screen is not the problem as when I connect it with a USB cable the PC also does not appear to have anything connected and won't make a noise.
I removed and replaced the battery and the battery is fully charged (reading 4.12V). I have tried connecting the calculator to other USB power sources but it refuses to turn on. I removed the battery and left it unpowered for a long time then tiered powering it on and it still won't turn on. I checked voltages appearing at the battery terminal with the USB plugged in and it is reading 4.12V. So all voltages are fine. There is another test point reading 1.8V.

It was updated to the latest 2016 firmware and was working fine before the exam. I bought it in 2013 when it came out in the UK.
Any idea on how to bring it back to life?

I made a video about it to see if anyone has any suggestions:
https://www.youtube.com/watch?v=xFRJtK7tsV0