where is lid switch on NC6400?

I have the issue of backlight not turning on on my NC6400. My guess is that the lid switch is faulty. But I can't figure out where the switch is located.

When I boot up, the screen flashes on for a second before the backlight turns off. With a bright light, I can still see the HP logo during boot up and the computer continue to boot into windows just fine. If I set the lid to the angle in which the computer lid is closed/open (the hdd indicator light changes color), sometimes I could get an instant of backlight.

I think the lid switch is stuck or broken, but I can't find it on the outside. Anyone know where the switch is? I'd also be happy with just letting the screen be on all the time if it comes to that.

Thanks.

 

Inverter cable that goes inside one display hinge is more probably the cause. When display is opened enough, one individual lead inside the cable disconnects (since it's broken) and connects again when lids is closed enough. That is very typical issue on many laptops.

Download the service manual from HP website, it may have some ideas on the switch. My 8510w doesn't have visible switch either, I have no idea where it is. Perhaps it is magnetic switch inside the lid?

 

Ah that sounds more likely now that I think about it. The inverter cable is only a few bucks on ebay, so I'll give it a shot. Thanks KLF.

 

Good call KLF!

For only $10 ($6 inverter board from ebay and $4 torx #8 screw driver from Sears), replacing the inverter board fixed the problem! A little stressful while opening up the laptop, but totally worth it. Thanks again KLF.

 

Great to hear it works now

I used to do such repairs for living some time ago. Inverter cable / board is still one of the simplest replacements.