Gateway M305 backlight revisited

I posted about this machine some weeks ago, but no replies....

Symptom: backlight refuses to come on. Image visible on lcd under close scrutiny. Laptop boots normally, except no backlight. Symptom happened suddenly. One boot before, everything appeared normal, then no backlight. The unit was out of my control up to that time, so I don't know what might have occurred in between. I do know the unit was transported immediately prior to the failure, but have no knowledge of any shock (or awe for that matter) incident.

Inverter? Replaced with NIB unit via eBay. Still no backlight.

Bulb? Subbed in known working bulb from another laptop. It doesn't light with new inverter.

So, where to go from here? There are four pins on the input side of the inverter. Two of them show voltage (? 5v dc). Has anyone got some idea of what they 'should' measure? I've jiggled all cables with no success. I've disassembled the base unit down to the plug which connects the display. Reseating that produces no joy.

I'm stumped....


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In an earlier similar post, someone suggested checking the sleep mode switch. That's the one activated by the LCD cover closing. In many if not most cases, the operation of these, causes the backlight to go out. I have come across dozens of such service calls as a technician.


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I checked the 'lid open' switch. That functions normally. Sleep mode on this unit is enable by closing lid, or momentarily toggling the power dedicated sleep switch.

Since last post I reassembled the unit and hooked up an external monitor. Everything functions normally, except when the internal LCD is switched off, its screen goes bright white (all pixels full on).

Background: this is a unit I bought new about four years ago, and handed down to wife and kids. I know it functioned correctly at one time. I used to use it for presentations with a projector. The screen would, of course, go black when the external LCD was enabled (unless it was in simultaneous LCD/VGA mode).

The only non-hardware thing that I can think of, is that wife had the hard drive wiped and XP Pro installed (originally had XP Home). Could this be a video driver issue?

This is not a major fault unless it signifies a more serious problem. Kids/wife are unlikely to use it thus.....


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jakdedert wrote in news:np5Yi.67173$ ....

What happens when you boot in safe mode?

You can go to the gateway web site.

formatting link
and download the drivers for the video. It would be a good idea to make sure all drivers are up-to-date anyway.

Also, make sure antivirus of some kind is installed and updated daily. Also, make sure that the microsoft updates are up-to-date.

bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
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