Tip & How-To about Acer Aspire 3680 Laptop

Troubleshooting Laptop Power Failures - Faint Image on Screen

Symptom

I can only see a very, very faint image of my operating system desktop on the screen.


Diagnosis & Solution

In such cases, the first thing to do is to plug in an external monitor and see if you could get a good image on it. If you get a good image on the external monitor, then this means that the video system is working, but the LCD isn't getting any backlighting. This could be due to either a failing backlight lamp or a failing inverter. The usual culprit is the inverter, especially if you didn't note any strange tinting to the laptop display in recent operation.

The traditional method used by technicians to test inverters is to connect it to a known good backlight lamp of the proper type, and test to see if the inverter could power up the backlight lamp or not. You could also test the inverter by connecting it to a good laptop screen that you might have salvaged from a dead laptop. If the inverter lights up the screen, then the inverter board is good and you are left with a bad backlight lamp as the cause of the problem. Otherwise, it is the inverter which is bad & needs to be replaced.

An alternate method to test the inverter is if you have access to a good quality RMS multi-meter, one that can measure frequency to 50 MHz or 100 MHz, you should be able to get a reading on a functioning inverter without even taking the lid apart. The inverter is normally located below the LCD in models with narrow borders, or to the side if there's an inch or so of plastic bezel on each side of the LCD. By scanning with the multi-meter probes over the plastic along the edge of the screen, you should pick up a strong signal somewhere between 30 KHz and 70 KHz if the inverter is live. If you can't pick up the signal but want to be sure, remove the plastic bezel from around the screen and measure right on the two insulated wires leading to the backlight. If the inverter is functioning, the meter will pick up the signal right through the insulation, since the inverter is putting out a low radio frequency signal.

Most of the time, a bad backlight lamp means that the whole LCD screen needs to be replaced.

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M. Omran

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Related Questions:

1 Answer

Screen goes black after 15 minuts of use


There are a few things that will cause this. One is power saving settings and the other is screen savers and then hardware issues. The software or operating system just needs to have the setting adjusted to make it behave. If you just need to wiggle the mouse or hit a key and you get the monitor back then this is all it it is. Sometimes the operating system gets stupid or someone changes it so that it thinks it is a laptop and needs to save the battery. So it shuts down things. You can check and change the settings under control panel and power settings.

The other thigns that do this are hardware. You can have a video card or the monitor as th cause. A high end video card has a fan on it and can overheat. The monitor won;t have a fan but will have vents and they do get dusty inside which can make them overheat. In that case you need to blow or vacuum out the dust. The other common failure is the power supply for the backlight. When the backlight goes out you don;t see a normal image. You should see a very faint ghost like image. You will have to get close to the screen and a bit off to one side. The backlight sort of projects the image so you can see it, so when it goes off the image or desktop is still there but very faint. If you see the faint image then the problem is the backlight and or backlight power supply. This should also happen when the monitor is plugged into another computer.

This is covered under warrenty but if not the repair parts should cost between $45 and $75 plus labor. This is a simple repair so some people just order the parts from a repair depot (search for acer monitor repair parts to find them) and change them out.



Aug 12, 2010 | Acer AL1916W 19" LCD Monitor

1 Answer

What causes this problem with the screen image going blank / faint image Goodmans 15.4 in. Flat screen lcd tv. I assume the tvs have a display/graphics card inside a bit like pcs. Is it economical to repair?


You dont give a model number to be able to give a correct diagnosis but i presume the back light invertor has failed or worse the lcd screen its self .
More info really required.

May 15, 2010 | Goodmans 15.4 in. LCD TV/DVD Combo

2 Answers

my advent laptop screen will not work i have plugged it into the tv which is pc compatible and it workd fine any ideas?


Hi,
Its sounds like you may have a faulty inverter but i need just a little more information from you before i can make a definite diagnosis and solution.

Turn on the laptop but don't connect it to the computer. Start to reposition the angle of the screen to see if the screen flickers.
If you see no flickering take the laptop into a room which has a strong light and position the lid at around 135 degrees.
Look very closely at the screen. Can you see a very faint image on the screen?
You may have to wait until the operating system has loaded before you will see anything, wait a minute or two.

Let me know what you see.

Sep 16, 2009 | Computers & Internet

1 Answer

faint or no picture on olevia / syntax tv model LT-37HVS


When you tune to a station and get sound I presume the screen is black so do the following.
Place a bright flashlight against the screen. Look for an image around the edge of the flashlight.
If you see an image the problem is probably one of three causes.

1) Power to the inverter board is bad.
2) Inverter board has failed.
3) The CCFT(cold cathode fluorescent light) are dead.

Someone knowledgeable in electronics can diagnosis it.

Mar 05, 2009 | Olevia LT37HVS 37 in. LCD HDTV

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