Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

1 post

Wannabe Geek

Topic # 6245 10-Jan-2006 11:46
Send private message

HI, was wondering if anyone could help me.
I have a nec versa m400,
intel p4 2.8 ghz, 512 sd ram, 60g hard drive, 15 tft xga, with intel extreme graphics. with win xp home.

I have had it for 1 1/2 years and quite recently it has started to make the screen go black everytime I plug in the external power.
You can still see the screen, if you look really closely but only just. If you remove the power the screen comes on again.
The computer runs fine on an external monitor. it is only with the tft screen.

All the windows power managment settings are set to 'never' as I thought this maybe a power saving problem. A friend also suggested bios power managment, but I dont seem to have an option for this in my bios menus.

If anybody can help or has any other suggestion please could you let me know.


Create new topic
Hawkes Bay
8477 posts

Uber Geek
+1 received by user: 5

Mod Emeritus
Lifetime subscriber

Reply # 26060 10-Jan-2006 14:45
Send private message

laptops generally have a switch, so that when you unplug the power, the screen dims automatically. (to save batteries).

It sounds like that switch is faulty. (i.e. hardware fault, not software).

Where did you buy it from? I have been researching the Consumer Guarantees Act lately, and even if your warranty has expired, 1.5 years for a power socket on a laptop would probably be covered by the CGA, and the retailer would have to put it right...

[OOPS, I see you are not in New Zealand. Sorry, I dont have a clue about consumer rights in the UK, but have left my answer intact for any kiwis facing similar issues.]

6 posts

Wannabe Geek

Reply # 27898 6-Feb-2006 17:45
Send private message

Sounds like a problem with your backlight inverter (that is a little circuit that produces a high voltage to power the small fluorescent light that lights up the screen from behind). A good clue is provided by Enchanted who points out that most laptops sense when the unit is running on batteries or external power and adjust the brightness to save power on the battery. You may find that the inverter is simply cutting out when the brightness is turned up. Experiment with this and turn the backlight brightness right down and then try switching between power and battery. I have seen exactly the same problem on a HP Pavillion notebook.



576 posts

Ultimate Geek
+1 received by user: 9

Reply # 27977 7-Feb-2006 22:47
Send private message

As greenjoe said it's most likely a problem with the FL Inverter.

You can test it to some extent by plugging/unplugging the external power in your case, or cycling from LCD to external video and back (normally Function F4, or F5, etc.). If it lights up nice and bright, then goes dim all of a sudden it's most likely a crook inverter.


Working for Service Plus -

Authorised Service Agent for Apple, BenQ, Sony, and Toshiba - warranty & non-warranty repairs.

Create new topic

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.