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Non-working backlight in phone LCD, suggestions?

FNET

Aug 29, 2011
2
Joined
Aug 29, 2011
Messages
2
Hello,

The backlight to my Nokia E72 has stopped working. I can still see the screen if I shine a torch on it. I thought it might be a broken LCD but I have purchased a new LCD screen and it is still doing the same thing.
So I think it might be a problem with the connector on the phone board. I got some rubbing alcohol and cleaned the contact with a qtip but it hasnt seemed to have helped the problem. The backlight is still not working and I can only see the screen if I shine a torch on it.

Do you have any suggestions as to what I could try next?

Thanks.
 

davelectronic

Dec 13, 2010
1,087
Joined
Dec 13, 2010
Messages
1,087
Phone lights broken

Hi and welcome FNET.
More batterys and a spare bulb.
Only joking, ive had my far share of mobile phones in pieces, use a magnifier to look for damaged or burnt out resistors or damaged led's, all this means stripping the phone to pieces, pain staking stuff, most of the stuff is like micro or nano, modular, it might be one component, or a whole board or sub board that needs replacing, time patience, and some luck. Dave. PS dirt dust pocket debris is the worst offender. :)
 

FNET

Aug 29, 2011
2
Joined
Aug 29, 2011
Messages
2
Hello again,

The LCD backlight is still not working, do you have any suggestions for where to look on the board? From what I can see, there is nothing burnt out or damaged.

Thanks
 

davelectronic

Dec 13, 2010
1,087
Joined
Dec 13, 2010
Messages
1,087
phone back light

Hi FNET.
I would strip it down until i got to the base board, main board, led display is usually above this, when i said dirt, i meant between conductive contact surfaces, use an air blower, small artists brushes and isoprophil alcohol to clean, even under the contact numerical pad, this is screwed down, gold plated contacts underneath, if you check all this and still no back light then it probably the circuit, and a fault to look for, so many models of phone they all use different circuit design to drive the display and back light settings, beyond the obvious it a shop or manufacturers job, warranty ? if yes dont do it send it back for repair. Dave. :)
 

bbhoyz

Sep 5, 2011
2
Joined
Sep 5, 2011
Messages
2
try this..follow this diagram and check the lines
L2451connectedtoVAUX1.jpg
[/IMG]

VAUX1line.jpg
[/IMG]

C1105location.jpg


connectthispoint-1.jpg
[/IMG]

actual pictures front near the lcd connector
actualpicL2451jumper-1.jpg
[/IMG]

back,
actualpicc1105jumper-1.jpg
[/IMG]


hope it can help..=)
 
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