# COMPAQ HP NC6400 NO DISPLAY ONLY BACKLIGHT, works on external monitor !



## ken3009 (Feb 27, 2008)

so there is no display and it only has this backlight. it works fine on my tv screen when i connect to the tv through a vga cable.
i did not drop it or do anything, there is no physical damage to screen. im typing this on my tv connected to it.

so my question is, what is wrong with it and should i replace the screen??
can i do this myself, cos i heard u only need a screwdriver to replace the screen?
tried fn+f4 but did not work. someone suggested i go to bios setup and load to defaults, but i dunno how to do this exactly. i press f8 on startup, but the setup screen does not come up on my tv

please help, id rather do this myself than go to a repair shop!!


----------



## JMPC (Jan 15, 2011)

The screen going dim can be the inverter or the back light. Both can be replaced but the process will vary by laptop. You should be able to find the parts on Ebay.


----------



## ken3009 (Feb 27, 2008)

well if you say it CAN be the inverter or blacklight, what else can it be. i can look for the parts, but r u sure thats whats wrong? tell me wut i need to do, ill do anything and let you know so you can come to an accurate conclusion about whats wrong. thanks a lot


----------



## ken3009 (Feb 27, 2008)

so you reckon i should by an inverter and that is the exact problem?


----------



## JMPC (Jan 15, 2011)

It's not easy to tell what the exact cause of the issue is. There's may some method of using a multimeter or similar test tool to diagnose the issue but it would still require disassembling the unit.

It's most likely the inverter or the back light. It's normally cheaper and easier to replace the the inverter but you need to make sure you get an exact replacement.


----------



## ken3009 (Feb 27, 2008)

This website has instructions on how to replace an inverter on my type of laptop, the hp nc6400
http://www.batterycentury.com/hp-nc6400-inverter-p-183564.html

i can also get the exact inverter.

are those instructions pretty accurate? if its that easy then i can pull it off.


----------



## JMPC (Jan 15, 2011)

Sounds like how I've done it but I've only ever done it on Dell laptops.


----------



## ken3009 (Feb 27, 2008)

i asked from a shop and they said it could likely be a graphics card or motherboard issue than an inverter issue.
and it will cost more for the motherboard and graphics card replacement.

wut do u think? i think i should buy an inverter and try that out myself first as it would be much cheaper that way.


----------



## JMPC (Jan 15, 2011)

If you're able to use an external monitor then I would start with the inverter. If it were the video adapter or the motherboard then I would think the external video output would be affected.


----------



## ken3009 (Feb 27, 2008)

ya good point, why didnt the guy at the store tell me this. cheers ill try that and post back


----------



## ken3009 (Feb 27, 2008)

i must also add that when i connect my pc to the tv, the tv does not display the screen most the time when i toggle with Fn+F4(lcd screen) keys. it just flickers most of the time in the "PC VGA" mode...but sometimes it works fine on the tv. what does this say?
is there something wrong with the graphics card , gpu, or motherboard?
but once im able to get it on tv, it never flickers or faulters. so i dont know why it shows on tv sometimes, and other times it doesnt.

i tried shaking laptop but still does not show on tv most the time.

why could this be?


----------



## indytycoon (Apr 8, 2011)

I am a computer tech and I have one of those exact same laptops doing the exact same thing. I replaced the screen and the inverter, a couple of times as we have a bunch of these laptops. Still does not work. It appears to be a mainboard problem.


----------



## ken3009 (Feb 27, 2008)

so the fact is, it flickers when attempting to display on tv (just flashes, no display, just a light), but once it does get on tv it never flickers.
so there is some problem when toggling from pc to tv screen. i cant understand why


----------

