LCD Dims When AC Adaptor Plugged In

Question

The LCD on my Dell Inspiron 8600 dims when i plug in the AC adapter.

rickmktg · Answer

@srauda wrote:

The LCD on my Dell Inspiron 8600 dims when i plug in the AC adapter.

Check your settings in BIOS, F2 on startup, where you decide the brightness of the screen on battery or AC power. YOu can also hit the keys to change brightness which are a blue sun and you hit the FN key first.

Leo_s84 · Answer

Read again, and this time really read it:   Quote from rickmktg:   'Check your settings in BIOS, F2 on startup, where you decide the brightness of the screen on battery or AC power.'

srauda · Answer

And how does that explain why the lcd does NOT dim when the AC adaptor is NOT plugged?

srauda · Answer

Guess i did not give enough detail.

If i boot up with the AC adaptor plugged or if i simply plug in the adapter, the LCD dims to an unviewable level after a short period of time.

If however, i boot up with the AC adaptor unplugged the LCD remains luminated at the usual level.

srauda · Answer

What is the solution?

srauda · Answer

Ok. Did as told and the meter is maxed for both AC and Battery.

So this is what happens with AC plugged.

1. Boot up.

2. Logon to windows.

3. Brightness is still ok.

4. After a few minutes or so, screen becomes almost unviewable.

With AC unplugged, screen remains at normal brightness.

Thanx for the help.

johnallg · Answer

The lcd inverter board is overheating and shutting down on AC (probably higher voltage to it).  Usually indicative of the lcd backlights going bad.

srauda · Answer

Ok. I tried this.

1. Boot up with AC adaptor NOT plugged.

2. Log into windows.

3. LCD at normal brightness at this point.

4. Plug in AC adaptor. LCD flickers for a few moments then goes almost completely dark. Can still faint image.

Any ideas?

insp1150_14CK56 · Answer

Bad video card, have dell fix it, its slowly frying...

srauda · Answer

Please explain why it would be the video card. thanx

Leo_s84 · Answer

'Bad video card, have dell fix it, its slowly frying...'   Wow, that doesnt make any sense...how did you reach that conclusion

johnallg · Answer

It isn't the video card!  The backlight going out doesn't happen on battery for two reasons - the voltage is slightly lower and thus the inverter doesn't overheat, or the power handling on the motherboard is causing it.  Call Dell for warranty work.

srauda · Answer

Out of warranty. What are my options?

johnallg · Answer

Backlight tube replacement or replace the lcd.   Another thought - have you tired lowering the brightness down all the way and see if it will stay on?  I have always run my LCD at the dimmest and after just shy of 4 years have not had a problem.  Yet.  Knock on wood!  Message Edited by johnallg on 02-12-2005 12:04 AM

rickmktg · Answer

@johnallg wrote:

I have always run my LCD at the dimmest and after just shy of 4 years have not had a problem. Yet. Knock on wood!

I have this vision of Mr. Magoo with those really big glasses on trying to read a dim screen... :smileyvery-happy:

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