Re: Gateway M305 backlight revisited

hemyd wrote:
"jakdedert" <jakdedert@xxxxxxxxxxxxx> wrote in message news:rJqXi.3010$di.387@xxxxxxxxxxxxxxxxxxxxxxxxx
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....

jak


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.

Henry.

I checked the 'lid open' switch. That functions normally. Sleep mode on this unit is enable by closing lid, or momentarily toggling the power switch...no 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.....

jak

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Relevant Pages

  • Backlight and LCD module patches [2]
    ... This patch adds lcd and backlight driver classes so that the ... +struct lcd_properties { ... * class is registered before users of the class try to register lcd's ...
    (Linux-Kernel)
  • Re: LCD Monitor has very low display quality at 800x600 setting
    ... condition that is effected by a flickering fluorescent light ... light behind the LCD display and that is how it works. ... Try turning the backlight off and use ... to the NEC ...
    (microsoft.public.windowsxp.hardware)
  • [PATCH] fbdev: Statically link the framebuffer notification functions
    ... The backlight and lcd subsystems can be notified by the framebuffer layer ... separate out the framebuffer notification mechanism from the ...
    (Linux-Kernel)
  • Re: Linux 2.6.12-rc2
    ... >> I'm not sure what's up here, it's a nasty issue with backlight. ... > backlight remains switched off and if I switch it on with radeontool it ... but the LCD still didn't ... send the line "unsubscribe linux-kernel" in ...
    (Linux-Kernel)
  • Re: Inspiron 6000 Backlight Replacement
    ... I have not determined the exact problem but am wondering if replacing a backlight is something an intermediate computer tinkerer can do. ... I have no reservations about taking apart notebooks and if the backlight is the problem replacing it would be way cheaper than a $150 to $300 LCD... ... Don't know if the Inspiron 6000 has an nVidia chip or whether it is part of the motherboard or part of a separate snap-on proprietary graphics card. ... It may also be that either the backlight connector is loose inside the LCD screen or that the cable connecting to the laptop motherboard is simply loose. ...
    (alt.sys.pc-clone.dell)