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Picture Fault LG 42LF66
ProDave:
--- Quote from: pan on December 23, 2011,10:44:51 ---Hi,
..... which eventually course the backlight to turn off.
--- End quote ---
I think that bit is significant.
If it was JUST a panel or tcon fault, why would the backlights go off?
I would be looking at the inverter.
I have had 3 sets now where the inverter causes interference. On one set it just made a buzzing noise on the sound, on the second it interfered with the IR receiver, and on the third, it caused picture break up on freeview.
So if my hunch is correct, interference from the inverter could be causing picture interference.
What I found an the 3 sets (all different) that had this problem, was backlight intensity was important. In all cases, setting the backlights to full brightness stopped the interference.
So if you have backlight intensity in any of the menu's, set it to full and see if it makes any difference.
daz:
I would also take the screen apart and check for any arcing around the backlight tube holders
good luck
Daz
tv tony:
From memory I think the inverter brightness is pwm controlled and this has been known to cause problems, ill dig my notes out over the next day or so.
Tony Walker
pan:
Hi Guys,
I was doing some further tests when I noticed something.
As you can see from the photo (I know its miniature) I’ve got the set connected to a signal generator, connected to AV1 by scart.
As the fault started to occur I pressed the input button on the TV remote, and by mistake selected DVB, there is no aerial connected to the TV the DVB symbol was clear to see top right hand corner of the screen no distortion at all, when on DVB I selected the main menu, the main menu came onto the screen as clear as a bell no distortion/breakup I left the set on test for some time and it was fine.
When I selected AV1 the colour bars came back on distorted and after a matter of minutes the back light turned off.
Guys I’m I missing something?
Regards
Pan
pan:
Hi
I guess I’m a little naive/ inexperienced when it comes to picture faults on LCD TVs.
But I thought when there is a picture problem; picture break up it would affect the menus on the other inputs.
When I place my meter probe on any one of the 2 wires of the 10 plugs on the master or slave inverter boards the backlight turns off.
I’m thinking the picture interference after a time is the backlight assembly going intermitted with this TV.
I’ve not got a clean room workshop that I understand is required to repair screens/replace CCFL tubes.
Daz did say it could be the tube holders; I’m inclined to believe that could the prob.
If anyone has any thoughts please can you share them with me
Ta
Pan
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