You don't know til you try . . .

Laptop backlight woes

, posted: 4-Jul-2012 09:46

You know the story, turn the laptop on and screen is dark.
It makes all the right noises.
In order of least to most expensive fix.
Cables - Inverter - CCFL Tube - Screen - Mainboard

In my case I could still see a image with a torch shining on the screen.
It also flickered on briefly at boot.

YNV-18 , HP 8730W
I scoped the pins to make sure it wasn't the mainboard.
7 pin connector.
1+2 , Vcc, either battery or pluged in ac adaptor.
3+4 , Gnd
5,6,7 Didn't note exact allocation at the time,
PWM (for brightness control), Enable Backlight (active high), Enable Light sensor (active high)

The hunt for an inverter began.
A used replacement was located online.
us$14 including shipping.
Even with the fastest shipping it was 4+ days away so went with standard shipping 5-14 days.

On to Trademe for something temporary.
There were a few pin compatible units available.
Purchased one.
Tried a few when I went in to collect.
No go :(
Grabbed a known working one that wasn't pin compatible and tried my luck.

It was also 7 pin.
Wired the 3 control signals to the Enable backlight line.
It works :)
I didn't make the joining cables long enough, otherwise I could have put the cover back on.
No major, just wait for proper one to arive.
I can still close the lid.
Full brightness all the time though.

I also contemplated and upgrade to a LED backlight.
Nearly double the brightness would come in handy during summer outdoors.
Unfortunately they don't hav e a 17" kit.
No eta on one either.
I could have joined two 8.4" kits together.
May still do if I find this too dim outdoors.

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Comment by Skolink, on 4-Jul-2012 15:17

Good work! A friend got his 'professionally' replaced by a computer company not so long ago. When he got it back the backlight worked but the inverter was so loud the laptop was unusable (except with an external monitor).
He eventually took it back, and it was repaired again, now only has a faint whine coming from inverter. Still not ideal, esp considering the ~$300 fee.

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