Laptop monitor dim and blinking

[Jeremiah58]

Laptop is HP Pavillion dv9700. 4 years old, hasn't been used very often.

When it is run on a battery, the monitor is very, very dark and blinking.
But when I plug in an AC adapter, the monitor works normally.

Is it a battery or something else?
I'm a bit puzzled, because if it is a battery, I would expect the laptop to shut off.
Any advice, please? Thank you in advance.

[johns0]

Either the battery is bad and isn't charging fully anymore or the battery isn't fully charged.The laptop will reduce its power drain by dimming the lights,when it reaches a critical power point then the laptop won't start anymore.

Have you charged the lt overnight?If you did then it needs a new battery.

[Jeremiah58]

Thank you for your reply.
Yes, the battery has been charged to 100%, but the problem remains.

[KBeee]

Have a look at your Control Panel/Power Options/adjust the display brightness. There is often a lower setting selected for when running on battery to lengthen battery life.

[Jeremiah58]

Have a look at your Control Panel/Power Options/adjust the display brightness. There is often a lower setting selected for when running on battery to lengthen battery life.

Yes, I'm aware of that. I've been keeping it on factory settings "HP recommended".
Well, I will order a new battery. These days the prices are affordable.
Thank you.

[TBoneit]

It isn't the battery. If the battery does not have enough charge the laptop will just shut down.

Try bringing up the brightness while on battery. Your backlight may be getting old and at low brightness levels it is acting up. Try turning up the brightness when it is running on battery to match the brightness when on the AC Adapter.

Good Luck
TB

[turk690]

If the battery is replaced & it still behaves the same way, chances are the LCD backlight fluorescent lamps are about to die, or the inverter driving them is, or both. Not an unusual problem with those. You are now going to be charged an arm, a leg, & 2 molars to have HP powers-that-be replace those wretched lamps and/or inverter...

[Nelson37]

I agree with Kbee and Tbone. Turn up the brightness while on battery as a test. Zero cost, Instant answer. HP recommendations do not take into account the bulb getting weak.

[Jeremiah58]

Try bringing up the brightness while on battery. Your backlight may be getting old and at low brightness levels it is acting up. Try turning up the brightness when it is running on battery to match the brightness when on the AC Adapter.

I've just tried that. I turned the brightness on to 100% and nothing happened while on a battery. When I plug in the AC adapter, this increase in brightness is clearly visible, so I reduced it to normal brightness.
I've already ordered the more powerful 12-cell battery replacement from Amazon. I'll report here when I receive it.
Thank you very much for all replies.

[Jeremiah58]

Finally I've received a new battery, bought from Amazon.us.
38$ plus 15$ postage to Europe.
I charged it overnight to 100 %, as recommended by manufacturer (Anker), tested it and... No, it's not the battery, as some of you already suggested.
I've got the same problem with the screen. No improvements.

But why it works normally with AC adapter?

[jollyjohn]

It's not a big deal to change/replace a screen on a laptop. I've done a few times. Google for instruction videos. You don't need special tools.