1 Nickel

Latitude E6420 halts *before* POST

Hi folks,

This is a head scratcher. This is my work laptop that is only used occasionally for testing vendor demo gear, attending training classes, etc, mostly Audio Visual related programs and gear like Crestron, Biamp, etc and equipment they control. It really hasn't seen a lot of use over the years, spending most of its days sitting in its case at my desk. 

So, I have an AV installation trip coming up soon and was going to bring it with me for Crestron and Biamp programming if needed, so I brought it home the other day to update the Windows and Crestron software (no Internet connection for it at work). Everything installed great and it updated everything, and restarted after the updates, no issues. I closed the lid to put it to sleep, so I could sleep (it was in my bedroom).

The next morning I opened the lid and hit the power button and the power button lit up and that's about it. No post, no screen text, nothing. Just the power and battery light on (if plugged in), both on the keyboard and on the lid LEDs near the hinge. Plugging in external monitors (VGA or HDMI) didn't show anything either, so it's not the display. I can also eject the DVD drive when power is on, and the fan runs at idle speeds when powered on.

Here's the weird thing...during all my troubleshooting, sometimes it starts up fine (if the hdd light flashes when I press Power, I know it'll start).

So, here's what I've found in my troubleshooting:

  • It doesn't appear to be the RAM (2x4G), as I've tried starting it up with either and both, in all slot arrangements. Sometimes it starts, sometimes it doesn't (usually doesn't).
  • If I remove the RAM, it rightly gives me the 3-LED code for "can't detect RAM" (solid HDD led and blinking battery and wifi led).
  • If it does start with only one of the 2 RAM cards, it rightly gives me the POST text warning of changes in the RAM.
  • If it has started up into Windows, and I "restart" from within Windows, it soft reboots and comes back fine. However, if I "Shutdown" from within Windows (full shutoff), and then press the power button, it doesn't start up, same issues.
  • Sometimes when I press the Power button, the Caps Lock button light flashes, but not always.
  • If I use a bootable disk in the DVD drive, such as a Windows Disk, MemTest disk, Helix disk, whatever, it will spin up the DVD but that's it...it spins up, goes idle and then no other response. (I have it set to boot USB, CD/DVD drive, then hard drive.)
  • When I shut down power from its "stuck" state, the fan spins up high for a few seconds and then there is a click near the hard drive and then it shuts off (that click might be normal, I don't remember).
  • It doesn't matter if its on battery power or AC power, or whether or not the hard drive is installed (attempting to boot up on DVD when the HDD is out, of course).
  • I've even tried having the display in different positions (full flat open to barely open) just in case there's some cable in the hinge that is intermittently opening to cause the issue, but no change.

When it's up and running, it acts like there is no problem. I thought I had it fixed last night after disassembling and reassembling it after making sure there were no obvious loose/pinched wires or cards, using it for a few hours to do some programming, even installing a wifi USB dongle (it has no wifi card) and rebooting afterward. But then this morning it wouldn't start up again after simply closing the lid last night.

So, any ideas?



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2 Replies
8 Krypton

Re: Latitude E6420 halts *before* POST

I didn't see where you mentioned updating the chipset driver. While the laptop was connected, did it download any Windows updates? If it is unpowered, it should have had to install several hundred megabytes of Windows updates.
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1 Nickel

Re: Latitude E6420 halts *before* POST

I have not updated the chipset driver, and it did do some Windows updates, although I'm not sure how many. This isn't the first time it's ever been updated, though, I bring it home a couple/few times a year. 

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