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Every once in a while, I boot the computer and the video output refuses to work, before the Dell logo in the bios shows up. The back light works, and the computer is booting up behind the scenes (I can eventually shut the computer back down by moving the mouse to the right places and clicking), but there's no video display.

When this happens, power cycling doesn't do anything: it just boots back to a uncooperative video output. A few times, power cycling 20 times or more eventually got the screen working. Leaving the computer shut off for a while sometimes worked. Holding down the fn key to start a diagnostic test, and then power cycling sometimes worked. And now, apparently toting the laptop around the city brought the video output back.

Removing/inserting the battery never works. Booting up into an OS (dual Ubuntu/Windows 7) and shutting down doesn't work.

It seems that most of the time putting the computer on standby or hibernating (usually from Ubuntu) precedes a 'black out'. However, it doesn't always happen: maybe twice a week, for a few weeks now.

Doesn't seem like it's strictly hardware: it sometimes works, sometimes doesn't, and eventually works (thinking that if something failed, it'd fail all the time). Doesn't seem to be strictly software, either, or it wouldn't happen before BIOS, and wouldn't persist through power offs.

No, I didn't have an external monitor to test the video output from my VGA port. Sorry about that, I'll have to find a free monitor somewhere.

Any ideas on what might be causing this and/or more diagnostics? Take it to a tech?

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up vote 0 down vote accepted

I would try toggling video output. The root of the problem could be a blown capacitor somewhere that delivers inappropriate charge making the switch happen. Power cycling and the problem sometimes going away or leaving it disconnected fixing it points to power supply or blown capacitor issues.

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