Laptop Dim screen, very dark barely make out screen display

September 10, 2013 at 15:44:52
Specs: Windows Vista
I have an emachines e525. whenswitching on boots up fine but you cannot see anything on the screen. If i connect to an externalmonitor i cansee everything fine but you can only slightly make out the display on the laptop screen.

i have tried reading up on this, apparently the inverter is at fault, so i order the part and tried replacing but still same problem. maybe i didnt install new part correctly i don't know.

please help someone.


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#1
September 10, 2013 at 16:55:40
If the old inverter didn't work and the new one doesn't either, it s possible the power cable to the inverter is bad. If your have a voltmeter, test if there is voltage coming from the cable.

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#2
September 13, 2013 at 07:38:09
Thank you THX1138,

I have acquired a voltmeter, however not to sure how to make use of it and what to be looking for. a bit new to all this electronic stuff. could you (or someone) shed a bit more light on this. how i check the cable, what voltage i am looking for, how to set the viltmeter etc.

Thanks in advance appreciate it


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#3
September 13, 2013 at 07:55:48
It is possible that the original inverter was fine and it is the back light itself that is faulty. The back light is a cold cathode fluorescent tube which does not last forever.

If you were to take the laptop into a service centre for repair with those symptoms the engineers would replace both the inverter and the back light as a matter of routine. It is not worth the effort to work out which on is faulty so both are replaced.

The new breed of LED back lights are much more reliable and last a lot longer and do not need an inverter as they work of DC.

Stuart

message edited by StuartS


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Related Solutions

#4
September 13, 2013 at 08:08:14
so what your saying is that it may not be the power cable for the inverter or anything to do with the inverter at all as afforementioned.

how would i go about replacing the backlight (cathode tube), is it simple straightforward, where is it located? looks interesting the different ideas of what is causing the problem and what the solutions are.


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#5
September 13, 2013 at 08:28:14
The back light is located next to the screen, usually two, one either side. You can trace the output leads from the inverter to the back light,

You need to dismantle the screen to get at them but once you have done that they are fairly simple to replace.

Stuart


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#6
September 13, 2013 at 08:29:28
Stuart is most likely right, I didn't even think about the light itself being bad. But before you run out and spend more money on a new tube, I would still suggest making sure the inverter is getting voltage.


The cable coming from the motherboard that goes to the inverter should have two wires. Set your voltmeter to measure voltage and touch the leads to the two wires. If it reads a voltage, then it's most likely a bad light. If you don't see any voltage, then it's possible the cable or something on the motherboard that's gone bad


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#7
September 13, 2013 at 08:31:49
That makes sense, i will definitely try checking the voltage first and if it seems fine i will look at replacing the cathode tube or backlight

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#8
September 13, 2013 at 09:59:52
You can also use the voltmeter to check the output from the inverter. Only make sure you switch to AC or you wont get a reading at all.

Stuart


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