RE: Latitude E6420 wont boot, screen is black, cannot interpret LED error signals
I disagree with your interpretation of the error signal. After greatly enlarging the table from its current form, I was able to determine that blinking battery and wireless LEDs indicate a RAM problem, so I reseated the RAM and the computer is happier, though not completely cured yet. I could understood why a RAM stick might rebel when a 9volt ohmeter is applied to its motherboard, although I'm pretty sure I had removed the RAM when I did that.
It would have been helpful to know where the table of error signals is found.
Also, I'd love to know anyone's fix to the bitlocker lockout problem. I tried to copy the recovery image for this computer from Dell support but when I tried it failed and the error message said to contact Dell Technical support. All they would say is that the computer is no longer covered by a warranty, no other clues.
If anyone has better clues on how to overcome the bitlocker lockout I'd love to read them, although I think I'm just a few minutes away from getting this computer to work using my brute force reset.
If anyone is interested I'll post how it goes.