JojoWilliams
1 Copper

Latitude E6420 wont boot, screen is black, cannot interpret LED error signals

9 days ago I was given an E6420 that was quite healthy but protected by bitlocker and I had no password.  Since then I've tried every trick to recover and all have failed.  The BIOS is locked so I could not change any settings, not even the date.  On boot up the system asked for a password before letting windows 7 run.

I figured if I formatted the HD and started over all would be OK, and after a great deal of difficulty, I did that on another computer.  But bitlocker was still there.

I looked for ways to "zeroize" or reset the BIOS and failed.  I disconnected the big and coin batteries and shorted the terminals overnight and started again.  Nothing changed.  I took an ohmeter and touched it to the battery terminals with the battery removed to force a reset.  That changed things.  Now, when I boot it, the screen is black and two LEDs flash.  I cannot find anyplace to decrypt the flashing LED error signal on start up, white battery and wireless LEDs flashing. 

It now acts like an uncoordinated collection of wires and chips.  I meant to make it forget it had bitlocker protection but went far beyond.

I'd love to read any suggestions.  The dell site has not been helpful at all, unlike every other Dell I've worked on. 

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Moderator
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RE: Latitude E6420 wont boot, screen is black, cannot interpret LED error signals

Seems like a motherboard issue. You can use the image below to decipher the LED codes.


Image


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JojoWilliams
1 Copper

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.

 Jojo

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JojoWilliams
1 Copper

RE: Latitude E6420 wont boot, screen is black, cannot interpret LED error signals

The computer boots as before but wants to do system recovery and starts that process and after 15 minutes or so gives up.  The BIOS wont let me change to boot from the CD drive to reload Windows so I'm back to almost where I began.

Does anyone know a solution?

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