I have a unorthodox method to try and get it to boot.
Open the top cover with the unit unplugged.
Put a small screw driver , pin, screw in the fan slot so it doesn’t spin.
power unit on, ensure the fan does not spin.
Unit should throw a new error , beep twice , and then boot.
You can also try to do this from the back fan slot without opening it.
It needs to stop the fan spinning for this to work.
Note: this is not recommended to continue to use this device for production. You likely either have a corrupt compact flash, a IC chip that has a thermal event, or a bad fan/rpm sensor.